From 1b29a00267f864a7b420e388f06918a330ea8d2a Mon Sep 17 00:00:00 2001
From: Rachel Fenichel <fenichel@google.com>
Date: Wed, 3 Nov 2021 10:34:27 -0700
Subject: [PATCH] chore: update php block generators to const and let (#5663)

---
 generators/php/colour.js     |  26 ++---
 generators/php/lists.js      | 220 ++++++++++++++++++-----------------
 generators/php/logic.js      |  44 +++----
 generators/php/loops.js      |  53 ++++-----
 generators/php/math.js       |  99 ++++++++--------
 generators/php/procedures.js |  56 ++++-----
 generators/php/text.js       | 148 ++++++++++++-----------
 generators/php/variables.js  |   6 +-
 tests/deps.mocha.js          |  16 +--
 9 files changed, 347 insertions(+), 321 deletions(-)

diff --git a/generators/php/colour.js b/generators/php/colour.js
index 320949fc6..59e55e7f1 100644
--- a/generators/php/colour.js
+++ b/generators/php/colour.js
@@ -16,31 +16,31 @@ goog.require('Blockly.PHP');
 
 Blockly.PHP['colour_picker'] = function(block) {
   // Colour picker.
-  var code = Blockly.PHP.quote_(block.getFieldValue('COLOUR'));
+  const code = Blockly.PHP.quote_(block.getFieldValue('COLOUR'));
   return [code, Blockly.PHP.ORDER_ATOMIC];
 };
 
 Blockly.PHP['colour_random'] = function(block) {
   // Generate a random colour.
-  var functionName = Blockly.PHP.provideFunction_(
+  const functionName = Blockly.PHP.provideFunction_(
       'colour_random',
       ['function ' + Blockly.PHP.FUNCTION_NAME_PLACEHOLDER_ + '() {',
        '  return \'#\' . str_pad(dechex(mt_rand(0, 0xFFFFFF)), ' +
           '6, \'0\', STR_PAD_LEFT);',
        '}']);
-  var code = functionName + '()';
+  const code = functionName + '()';
   return [code, Blockly.PHP.ORDER_FUNCTION_CALL];
 };
 
 Blockly.PHP['colour_rgb'] = function(block) {
   // Compose a colour from RGB components expressed as percentages.
-  var red = Blockly.PHP.valueToCode(block, 'RED',
+  const red = Blockly.PHP.valueToCode(block, 'RED',
       Blockly.PHP.ORDER_NONE) || 0;
-  var green = Blockly.PHP.valueToCode(block, 'GREEN',
+  const green = Blockly.PHP.valueToCode(block, 'GREEN',
       Blockly.PHP.ORDER_NONE) || 0;
-  var blue = Blockly.PHP.valueToCode(block, 'BLUE',
+  const blue = Blockly.PHP.valueToCode(block, 'BLUE',
       Blockly.PHP.ORDER_NONE) || 0;
-  var functionName = Blockly.PHP.provideFunction_(
+  const functionName = Blockly.PHP.provideFunction_(
       'colour_rgb',
       ['function ' + Blockly.PHP.FUNCTION_NAME_PLACEHOLDER_ +
           '($r, $g, $b) {',
@@ -53,19 +53,19 @@ Blockly.PHP['colour_rgb'] = function(block) {
        '  $hex .= str_pad(dechex($b), 2, \'0\', STR_PAD_LEFT);',
        '  return $hex;',
        '}']);
-  var code = functionName + '(' + red + ', ' + green + ', ' + blue + ')';
+  const code = functionName + '(' + red + ', ' + green + ', ' + blue + ')';
   return [code, Blockly.PHP.ORDER_FUNCTION_CALL];
 };
 
 Blockly.PHP['colour_blend'] = function(block) {
   // Blend two colours together.
-  var c1 = Blockly.PHP.valueToCode(block, 'COLOUR1',
+  const c1 = Blockly.PHP.valueToCode(block, 'COLOUR1',
       Blockly.PHP.ORDER_NONE) || '\'#000000\'';
-  var c2 = Blockly.PHP.valueToCode(block, 'COLOUR2',
+  const c2 = Blockly.PHP.valueToCode(block, 'COLOUR2',
       Blockly.PHP.ORDER_NONE) || '\'#000000\'';
-  var ratio = Blockly.PHP.valueToCode(block, 'RATIO',
+  const ratio = Blockly.PHP.valueToCode(block, 'RATIO',
       Blockly.PHP.ORDER_NONE) || 0.5;
-  var functionName = Blockly.PHP.provideFunction_(
+  const functionName = Blockly.PHP.provideFunction_(
       'colour_blend',
       ['function ' + Blockly.PHP.FUNCTION_NAME_PLACEHOLDER_ +
           '($c1, $c2, $ratio) {',
@@ -85,6 +85,6 @@ Blockly.PHP['colour_blend'] = function(block) {
        '  $hex .= str_pad(dechex($b), 2, \'0\', STR_PAD_LEFT);',
        '  return $hex;',
        '}']);
-  var code = functionName + '(' + c1 + ', ' + c2 + ', ' + ratio + ')';
+  const code = functionName + '(' + c1 + ', ' + c2 + ', ' + ratio + ')';
   return [code, Blockly.PHP.ORDER_FUNCTION_CALL];
 };
diff --git a/generators/php/lists.js b/generators/php/lists.js
index 8190672d4..bb27d6d83 100644
--- a/generators/php/lists.js
+++ b/generators/php/lists.js
@@ -32,8 +32,8 @@ Blockly.PHP['lists_create_empty'] = function(block) {
 
 Blockly.PHP['lists_create_with'] = function(block) {
   // Create a list with any number of elements of any type.
-  var code = new Array(block.itemCount_);
-  for (var i = 0; i < block.itemCount_; i++) {
+  let code = new Array(block.itemCount_);
+  for (let i = 0; i < block.itemCount_; i++) {
     code[i] = Blockly.PHP.valueToCode(block, 'ADD' + i,
         Blockly.PHP.ORDER_NONE) || 'null';
   }
@@ -43,7 +43,7 @@ Blockly.PHP['lists_create_with'] = function(block) {
 
 Blockly.PHP['lists_repeat'] = function(block) {
   // Create a list with one element repeated.
-  var functionName = Blockly.PHP.provideFunction_(
+  const functionName = Blockly.PHP.provideFunction_(
       'lists_repeat',
       ['function ' + Blockly.PHP.FUNCTION_NAME_PLACEHOLDER_ +
           '($value, $count) {',
@@ -53,17 +53,17 @@ Blockly.PHP['lists_repeat'] = function(block) {
        '  }',
        '  return $array;',
        '}']);
-  var element = Blockly.PHP.valueToCode(block, 'ITEM',
+  const element = Blockly.PHP.valueToCode(block, 'ITEM',
       Blockly.PHP.ORDER_NONE) || 'null';
-  var repeatCount = Blockly.PHP.valueToCode(block, 'NUM',
+  const repeatCount = Blockly.PHP.valueToCode(block, 'NUM',
       Blockly.PHP.ORDER_NONE) || '0';
-  var code = functionName + '(' + element + ', ' + repeatCount + ')';
+  const code = functionName + '(' + element + ', ' + repeatCount + ')';
   return [code, Blockly.PHP.ORDER_FUNCTION_CALL];
 };
 
 Blockly.PHP['lists_length'] = function(block) {
   // String or array length.
-  var functionName = Blockly.PHP.provideFunction_(
+  const functionName = Blockly.PHP.provideFunction_(
       'length',
       ['function ' + Blockly.PHP.FUNCTION_NAME_PLACEHOLDER_ + '($value) {',
        '  if (is_string($value)) {',
@@ -72,34 +72,34 @@ Blockly.PHP['lists_length'] = function(block) {
        '    return count($value);',
        '  }',
        '}']);
-  var list = Blockly.PHP.valueToCode(block, 'VALUE',
+  const list = Blockly.PHP.valueToCode(block, 'VALUE',
       Blockly.PHP.ORDER_NONE) || '\'\'';
   return [functionName + '(' + list + ')', Blockly.PHP.ORDER_FUNCTION_CALL];
 };
 
 Blockly.PHP['lists_isEmpty'] = function(block) {
   // Is the string null or array empty?
-  var argument0 = Blockly.PHP.valueToCode(block, 'VALUE',
+  const argument0 = Blockly.PHP.valueToCode(block, 'VALUE',
       Blockly.PHP.ORDER_FUNCTION_CALL) || 'array()';
   return ['empty(' + argument0 + ')', Blockly.PHP.ORDER_FUNCTION_CALL];
 };
 
 Blockly.PHP['lists_indexOf'] = function(block) {
   // Find an item in the list.
-  var argument0 = Blockly.PHP.valueToCode(block, 'FIND',
+  const argument0 = Blockly.PHP.valueToCode(block, 'FIND',
       Blockly.PHP.ORDER_NONE) || '\'\'';
-  var argument1 = Blockly.PHP.valueToCode(block, 'VALUE',
+  const argument1 = Blockly.PHP.valueToCode(block, 'VALUE',
       Blockly.PHP.ORDER_MEMBER) || '[]';
+  let errorIndex = ' -1';
+  let indexAdjustment = '';
   if (block.workspace.options.oneBasedIndex) {
-    var errorIndex = ' 0';
-    var indexAdjustment = ' + 1';
-  } else {
-    var errorIndex = ' -1';
-    var indexAdjustment = '';
+    errorIndex = ' 0';
+    indexAdjustment = ' + 1';
   }
+  let functionName;
   if (block.getFieldValue('END') === 'FIRST') {
     // indexOf
-    var functionName = Blockly.PHP.provideFunction_(
+    functionName = Blockly.PHP.provideFunction_(
         'indexOf',
         ['function ' + Blockly.PHP.FUNCTION_NAME_PLACEHOLDER_ +
             '($haystack, $needle) {',
@@ -111,7 +111,7 @@ Blockly.PHP['lists_indexOf'] = function(block) {
          '}']);
   } else {
     // lastIndexOf
-    var functionName = Blockly.PHP.provideFunction_(
+    functionName = Blockly.PHP.provideFunction_(
         'lastIndexOf',
         ['function ' + Blockly.PHP.FUNCTION_NAME_PLACEHOLDER_ +
             '($haystack, $needle) {',
@@ -124,80 +124,81 @@ Blockly.PHP['lists_indexOf'] = function(block) {
          '}']);
   }
 
-  var code = functionName + '(' + argument1 + ', ' + argument0 + ')';
+  const code = functionName + '(' + argument1 + ', ' + argument0 + ')';
   return [code, Blockly.PHP.ORDER_FUNCTION_CALL];
 };
 
 Blockly.PHP['lists_getIndex'] = function(block) {
   // Get element at index.
-  var mode = block.getFieldValue('MODE') || 'GET';
-  var where = block.getFieldValue('WHERE') || 'FROM_START';
+  const mode = block.getFieldValue('MODE') || 'GET';
+  const where = block.getFieldValue('WHERE') || 'FROM_START';
   switch (where) {
     case 'FIRST':
       if (mode === 'GET') {
-        var list = Blockly.PHP.valueToCode(block, 'VALUE',
+        const list = Blockly.PHP.valueToCode(block, 'VALUE',
                 Blockly.PHP.ORDER_MEMBER) || 'array()';
-        var code = list + '[0]';
+        const code = list + '[0]';
         return [code, Blockly.PHP.ORDER_MEMBER];
       } else if (mode === 'GET_REMOVE') {
-        var list = Blockly.PHP.valueToCode(block, 'VALUE',
+        const list = Blockly.PHP.valueToCode(block, 'VALUE',
                 Blockly.PHP.ORDER_NONE) || 'array()';
-        var code = 'array_shift(' + list + ')';
+        const code = 'array_shift(' + list + ')';
         return [code, Blockly.PHP.ORDER_FUNCTION_CALL];
       } else if (mode === 'REMOVE') {
-        var list = Blockly.PHP.valueToCode(block, 'VALUE',
+        const list = Blockly.PHP.valueToCode(block, 'VALUE',
                 Blockly.PHP.ORDER_NONE) || 'array()';
         return 'array_shift(' + list + ');\n';
       }
       break;
     case 'LAST':
       if (mode === 'GET') {
-        var list = Blockly.PHP.valueToCode(block, 'VALUE',
+        const list = Blockly.PHP.valueToCode(block, 'VALUE',
                 Blockly.PHP.ORDER_NONE) || 'array()';
-        var code = 'end(' + list + ')';
+        const code = 'end(' + list + ')';
         return [code, Blockly.PHP.ORDER_FUNCTION_CALL];
       } else if (mode === 'GET_REMOVE') {
-        var list = Blockly.PHP.valueToCode(block, 'VALUE',
+        const list = Blockly.PHP.valueToCode(block, 'VALUE',
                 Blockly.PHP.ORDER_NONE) || 'array()';
-        var code = 'array_pop(' + list + ')';
+        const code = 'array_pop(' + list + ')';
         return [code, Blockly.PHP.ORDER_FUNCTION_CALL];
       } else if (mode === 'REMOVE') {
-        var list = Blockly.PHP.valueToCode(block, 'VALUE',
+        const list = Blockly.PHP.valueToCode(block, 'VALUE',
                 Blockly.PHP.ORDER_NONE) || 'array()';
         return 'array_pop(' + list + ');\n';
       }
       break;
-    case 'FROM_START':
-      var at = Blockly.PHP.getAdjusted(block, 'AT');
+    case 'FROM_START': {
+      const at = Blockly.PHP.getAdjusted(block, 'AT');
       if (mode === 'GET') {
-        var list = Blockly.PHP.valueToCode(block, 'VALUE',
+        const list = Blockly.PHP.valueToCode(block, 'VALUE',
                 Blockly.PHP.ORDER_MEMBER) || 'array()';
-        var code = list + '[' + at + ']';
+        const code = list + '[' + at + ']';
         return [code, Blockly.PHP.ORDER_MEMBER];
       } else if (mode === 'GET_REMOVE') {
-        var list = Blockly.PHP.valueToCode(block, 'VALUE',
+        const list = Blockly.PHP.valueToCode(block, 'VALUE',
                 Blockly.PHP.ORDER_NONE) || 'array()';
-        var code = 'array_splice(' + list + ', ' + at + ', 1)[0]';
+        const code = 'array_splice(' + list + ', ' + at + ', 1)[0]';
         return [code, Blockly.PHP.ORDER_FUNCTION_CALL];
       } else if (mode === 'REMOVE') {
-        var list = Blockly.PHP.valueToCode(block, 'VALUE',
+        const list = Blockly.PHP.valueToCode(block, 'VALUE',
                 Blockly.PHP.ORDER_NONE) || 'array()';
         return 'array_splice(' + list + ', ' + at + ', 1);\n';
       }
       break;
+    }
     case 'FROM_END':
       if (mode === 'GET') {
-        var list = Blockly.PHP.valueToCode(block, 'VALUE',
+        const list = Blockly.PHP.valueToCode(block, 'VALUE',
                 Blockly.PHP.ORDER_NONE) || 'array()';
-        var at = Blockly.PHP.getAdjusted(block, 'AT', 1, true);
-        var code = 'array_slice(' + list + ', ' + at + ', 1)[0]';
+        const at = Blockly.PHP.getAdjusted(block, 'AT', 1, true);
+        const code = 'array_slice(' + list + ', ' + at + ', 1)[0]';
         return [code, Blockly.PHP.ORDER_FUNCTION_CALL];
       } else if (mode === 'GET_REMOVE' || mode === 'REMOVE') {
-        var list = Blockly.PHP.valueToCode(block, 'VALUE',
+        const list = Blockly.PHP.valueToCode(block, 'VALUE',
                 Blockly.PHP.ORDER_NONE) || 'array()';
-        var at = Blockly.PHP.getAdjusted(block, 'AT', 1, false,
+        const at = Blockly.PHP.getAdjusted(block, 'AT', 1, false,
             Blockly.PHP.ORDER_SUBTRACTION);
-        code = 'array_splice(' + list +
+        const code = 'array_splice(' + list +
             ', count(' + list + ') - ' + at + ', 1)[0]';
         if (mode === 'GET_REMOVE') {
           return [code, Blockly.PHP.ORDER_FUNCTION_CALL];
@@ -206,20 +207,20 @@ Blockly.PHP['lists_getIndex'] = function(block) {
         }
       }
       break;
-    case 'RANDOM':
-      var list = Blockly.PHP.valueToCode(block, 'VALUE',
+    case 'RANDOM': {
+      const list = Blockly.PHP.valueToCode(block, 'VALUE',
               Blockly.PHP.ORDER_NONE) || 'array()';
       if (mode === 'GET') {
-        var functionName = Blockly.PHP.provideFunction_(
+        const functionName = Blockly.PHP.provideFunction_(
             'lists_get_random_item',
             ['function ' + Blockly.PHP.FUNCTION_NAME_PLACEHOLDER_ +
                 '($list) {',
              '  return $list[rand(0,count($list)-1)];',
              '}']);
-        code = functionName + '(' + list + ')';
+        const code = functionName + '(' + list + ')';
         return [code, Blockly.PHP.ORDER_FUNCTION_CALL];
       } else if (mode === 'GET_REMOVE') {
-        var functionName = Blockly.PHP.provideFunction_(
+        const functionName = Blockly.PHP.provideFunction_(
             'lists_get_remove_random_item',
             ['function ' + Blockly.PHP.FUNCTION_NAME_PLACEHOLDER_ +
                 '(&$list) {',
@@ -227,10 +228,10 @@ Blockly.PHP['lists_getIndex'] = function(block) {
              '  unset($list[$x]);',
              '  return array_values($list);',
              '}']);
-        code = functionName + '(' + list + ')';
+        const code = functionName + '(' + list + ')';
         return [code, Blockly.PHP.ORDER_FUNCTION_CALL];
       } else if (mode === 'REMOVE') {
-        var functionName = Blockly.PHP.provideFunction_(
+        const functionName = Blockly.PHP.provideFunction_(
             'lists_remove_random_item',
             ['function ' + Blockly.PHP.FUNCTION_NAME_PLACEHOLDER_ +
                 '(&$list) {',
@@ -239,6 +240,7 @@ Blockly.PHP['lists_getIndex'] = function(block) {
         return functionName + '(' + list + ');\n';
       }
       break;
+    }
   }
   throw Error('Unhandled combination (lists_getIndex).');
 };
@@ -246,39 +248,40 @@ Blockly.PHP['lists_getIndex'] = function(block) {
 Blockly.PHP['lists_setIndex'] = function(block) {
   // Set element at index.
   // Note: Until February 2013 this block did not have MODE or WHERE inputs.
-  var mode = block.getFieldValue('MODE') || 'GET';
-  var where = block.getFieldValue('WHERE') || 'FROM_START';
-  var value = Blockly.PHP.valueToCode(block, 'TO',
+  const mode = block.getFieldValue('MODE') || 'GET';
+  const where = block.getFieldValue('WHERE') || 'FROM_START';
+  const value = Blockly.PHP.valueToCode(block, 'TO',
       Blockly.PHP.ORDER_ASSIGNMENT) || 'null';
   // Cache non-trivial values to variables to prevent repeated look-ups.
   // Closure, which accesses and modifies 'list'.
+  let cachedList;
   function cacheList() {
-    if (list.match(/^\$\w+$/)) {
+    if (cachedList.match(/^\$\w+$/)) {
       return '';
     }
-    var listVar = Blockly.PHP.nameDB_.getDistinctName(
+    const listVar = Blockly.PHP.nameDB_.getDistinctName(
         'tmp_list', Blockly.VARIABLE_CATEGORY_NAME);
-    var code = listVar + ' = &' + list + ';\n';
-    list = listVar;
+    const code = listVar + ' = &' + cachedList + ';\n';
+    cachedList = listVar;
     return code;
   }
   switch (where) {
     case 'FIRST':
       if (mode === 'SET') {
-        var list = Blockly.PHP.valueToCode(block, 'LIST',
+        const list = Blockly.PHP.valueToCode(block, 'LIST',
                 Blockly.PHP.ORDER_MEMBER) || 'array()';
         return list + '[0] = ' + value + ';\n';
       } else if (mode === 'INSERT') {
-        var list = Blockly.PHP.valueToCode(block, 'LIST',
+        const list = Blockly.PHP.valueToCode(block, 'LIST',
                 Blockly.PHP.ORDER_NONE) || 'array()';
         return 'array_unshift(' + list + ', ' + value + ');\n';
       }
       break;
-    case 'LAST':
-      var list = Blockly.PHP.valueToCode(block, 'LIST',
+    case 'LAST': {
+      const list = Blockly.PHP.valueToCode(block, 'LIST',
               Blockly.PHP.ORDER_NONE) || 'array()';
       if (mode === 'SET') {
-        var functionName = Blockly.PHP.provideFunction_(
+        const functionName = Blockly.PHP.provideFunction_(
             'lists_set_last_item',
             ['function ' + Blockly.PHP.FUNCTION_NAME_PLACEHOLDER_ +
                 '(&$list, $value) {',
@@ -289,24 +292,26 @@ Blockly.PHP['lists_setIndex'] = function(block) {
         return 'array_push(' + list + ', ' + value + ');\n';
       }
       break;
-    case 'FROM_START':
-      var at = Blockly.PHP.getAdjusted(block, 'AT');
+    }
+    case 'FROM_START': {
+      const at = Blockly.PHP.getAdjusted(block, 'AT');
       if (mode === 'SET') {
-        var list = Blockly.PHP.valueToCode(block, 'LIST',
+        const list = Blockly.PHP.valueToCode(block, 'LIST',
                 Blockly.PHP.ORDER_MEMBER) || 'array()';
         return list + '[' + at + '] = ' + value + ';\n';
       } else if (mode === 'INSERT') {
-        var list = Blockly.PHP.valueToCode(block, 'LIST',
+        const list = Blockly.PHP.valueToCode(block, 'LIST',
                 Blockly.PHP.ORDER_NONE) || 'array()';
         return 'array_splice(' + list + ', ' + at + ', 0, ' + value + ');\n';
       }
       break;
-    case 'FROM_END':
-      var list = Blockly.PHP.valueToCode(block, 'LIST',
+    }
+    case 'FROM_END': {
+      const list = Blockly.PHP.valueToCode(block, 'LIST',
               Blockly.PHP.ORDER_NONE) || 'array()';
-      var at = Blockly.PHP.getAdjusted(block, 'AT', 1);
+      const at = Blockly.PHP.getAdjusted(block, 'AT', 1);
       if (mode === 'SET') {
-        var functionName = Blockly.PHP.provideFunction_(
+        const functionName = Blockly.PHP.provideFunction_(
             'lists_set_from_end',
             ['function ' + Blockly.PHP.FUNCTION_NAME_PLACEHOLDER_ +
                 '(&$list, $at, $value) {',
@@ -314,7 +319,7 @@ Blockly.PHP['lists_setIndex'] = function(block) {
              '}']);
         return functionName + '(' + list + ', ' + at + ', ' + value + ');\n';
       } else if (mode === 'INSERT') {
-        var functionName = Blockly.PHP.provideFunction_(
+        const functionName = Blockly.PHP.provideFunction_(
             'lists_insert_from_end',
             ['function ' + Blockly.PHP.FUNCTION_NAME_PLACEHOLDER_ +
                 '(&$list, $at, $value) {',
@@ -323,11 +328,13 @@ Blockly.PHP['lists_setIndex'] = function(block) {
         return functionName + '(' + list + ', ' + at + ', ' + value + ');\n';
       }
       break;
+    }
     case 'RANDOM':
-      var list = Blockly.PHP.valueToCode(block, 'LIST',
+      cachedList = Blockly.PHP.valueToCode(block, 'LIST',
               Blockly.PHP.ORDER_REFERENCE) || 'array()';
-      var code = cacheList();
-      var xVar = Blockly.PHP.nameDB_.getDistinctName(
+      let code = cacheList();
+      const list = cachedList;
+      const xVar = Blockly.PHP.nameDB_.getDistinctName(
           'tmp_x', Blockly.VARIABLE_CATEGORY_NAME);
       code += xVar + ' = rand(0, count(' + list + ')-1);\n';
       if (mode === 'SET') {
@@ -345,36 +352,40 @@ Blockly.PHP['lists_setIndex'] = function(block) {
 
 Blockly.PHP['lists_getSublist'] = function(block) {
   // Get sublist.
-  var list = Blockly.PHP.valueToCode(block, 'LIST',
+  const list = Blockly.PHP.valueToCode(block, 'LIST',
       Blockly.PHP.ORDER_NONE) || 'array()';
-  var where1 = block.getFieldValue('WHERE1');
-  var where2 = block.getFieldValue('WHERE2');
+  const where1 = block.getFieldValue('WHERE1');
+  const where2 = block.getFieldValue('WHERE2');
+  let code;
   if (where1 === 'FIRST' && where2 === 'LAST') {
-    var code = list;
+    code = list;
   } else if (list.match(/^\$\w+$/) ||
       (where1 !== 'FROM_END' && where2 === 'FROM_START')) {
     // If the list is a simple value or doesn't require a call for length, don't
     // generate a helper function.
+    let at1;
     switch (where1) {
       case 'FROM_START':
-        var at1 = Blockly.PHP.getAdjusted(block, 'AT1');
+        at1 = Blockly.PHP.getAdjusted(block, 'AT1');
         break;
       case 'FROM_END':
-        var at1 = Blockly.PHP.getAdjusted(block, 'AT1', 1, false,
+        at1 = Blockly.PHP.getAdjusted(block, 'AT1', 1, false,
             Blockly.PHP.ORDER_SUBTRACTION);
         at1 = 'count(' + list + ') - ' + at1;
         break;
       case 'FIRST':
-        var at1 = '0';
+        at1 = '0';
         break;
       default:
         throw Error('Unhandled option (lists_getSublist).');
     }
+    let at2;
+    let length;
     switch (where2) {
       case 'FROM_START':
-        var at2 = Blockly.PHP.getAdjusted(block, 'AT2', 0, false,
+        at2 = Blockly.PHP.getAdjusted(block, 'AT2', 0, false,
             Blockly.PHP.ORDER_SUBTRACTION);
-        var length = at2 + ' - ';
+        length = at2 + ' - ';
         if (Blockly.isNumber(String(at1)) || String(at1).match(/^\(.+\)$/)) {
           length += at1;
         } else {
@@ -383,9 +394,9 @@ Blockly.PHP['lists_getSublist'] = function(block) {
         length += ' + 1';
         break;
       case 'FROM_END':
-        var at2 = Blockly.PHP.getAdjusted(block, 'AT2', 0, false,
+        at2 = Blockly.PHP.getAdjusted(block, 'AT2', 0, false,
             Blockly.PHP.ORDER_SUBTRACTION);
-        var length = 'count(' + list + ') - ' + at2 + ' - ';
+        length = 'count(' + list + ') - ' + at2 + ' - ';
         if (Blockly.isNumber(String(at1)) || String(at1).match(/^\(.+\)$/)) {
           length += at1;
         } else {
@@ -393,7 +404,7 @@ Blockly.PHP['lists_getSublist'] = function(block) {
         }
         break;
       case 'LAST':
-        var length = 'count(' + list + ') - ';
+        length = 'count(' + list + ') - ';
         if (Blockly.isNumber(String(at1)) || String(at1).match(/^\(.+\)$/)) {
           length += at1;
         } else {
@@ -405,9 +416,9 @@ Blockly.PHP['lists_getSublist'] = function(block) {
     }
     code = 'array_slice(' + list + ', ' + at1 + ', ' + length + ')';
   } else {
-    var at1 = Blockly.PHP.getAdjusted(block, 'AT1');
-    var at2 = Blockly.PHP.getAdjusted(block, 'AT2');
-    var functionName = Blockly.PHP.provideFunction_(
+    const at1 = Blockly.PHP.getAdjusted(block, 'AT1');
+    const at2 = Blockly.PHP.getAdjusted(block, 'AT2');
+    const functionName = Blockly.PHP.provideFunction_(
         'lists_get_sublist',
         ['function ' + Blockly.PHP.FUNCTION_NAME_PLACEHOLDER_ +
             '($list, $where1, $at1, $where2, $at2) {',
@@ -430,7 +441,7 @@ Blockly.PHP['lists_getSublist'] = function(block) {
          '  }',
          '  return array_slice($list, $at1, $length);',
          '}']);
-    var code = functionName + '(' + list + ', \'' +
+    code = functionName + '(' + list + ', \'' +
         where1 + '\', ' + at1 + ', \'' + where2 + '\', ' + at2 + ')';
   }
   return [code, Blockly.PHP.ORDER_FUNCTION_CALL];
@@ -438,11 +449,11 @@ Blockly.PHP['lists_getSublist'] = function(block) {
 
 Blockly.PHP['lists_sort'] = function(block) {
   // Block for sorting a list.
-  var listCode = Blockly.PHP.valueToCode(block, 'LIST',
+  const listCode = Blockly.PHP.valueToCode(block, 'LIST',
       Blockly.PHP.ORDER_NONE) || 'array()';
-  var direction = block.getFieldValue('DIRECTION') === '1' ? 1 : -1;
-  var type = block.getFieldValue('TYPE');
-  var functionName = Blockly.PHP.provideFunction_(
+  const direction = block.getFieldValue('DIRECTION') === '1' ? 1 : -1;
+  const type = block.getFieldValue('TYPE');
+  const functionName = Blockly.PHP.provideFunction_(
       'lists_sort',
       ['function ' + Blockly.PHP.FUNCTION_NAME_PLACEHOLDER_ +
           '($list, $type, $direction) {',
@@ -459,39 +470,40 @@ Blockly.PHP['lists_sort'] = function(block) {
        '  }',
        '  return $list2;',
        '}']);
-  var sortCode = functionName +
+  const sortCode = functionName +
       '(' + listCode + ', "' + type + '", ' + direction + ')';
   return [sortCode, Blockly.PHP.ORDER_FUNCTION_CALL];
 };
 
 Blockly.PHP['lists_split'] = function(block) {
   // Block for splitting text into a list, or joining a list into text.
-  var value_input = Blockly.PHP.valueToCode(block, 'INPUT',
+  let value_input = Blockly.PHP.valueToCode(block, 'INPUT',
       Blockly.PHP.ORDER_NONE);
-  var value_delim = Blockly.PHP.valueToCode(block, 'DELIM',
+  const value_delim = Blockly.PHP.valueToCode(block, 'DELIM',
       Blockly.PHP.ORDER_NONE) || '\'\'';
-  var mode = block.getFieldValue('MODE');
+  const mode = block.getFieldValue('MODE');
+  let functionName;
   if (mode === 'SPLIT') {
     if (!value_input) {
       value_input = '\'\'';
     }
-    var functionName = 'explode';
+    functionName = 'explode';
   } else if (mode === 'JOIN') {
     if (!value_input) {
       value_input = 'array()';
     }
-    var functionName = 'implode';
+    functionName = 'implode';
   } else {
     throw Error('Unknown mode: ' + mode);
   }
-  var code = functionName + '(' + value_delim + ', ' + value_input + ')';
+  const code = functionName + '(' + value_delim + ', ' + value_input + ')';
   return [code, Blockly.PHP.ORDER_FUNCTION_CALL];
 };
 
 Blockly.PHP['lists_reverse'] = function(block) {
   // Block for reversing a list.
-  var list = Blockly.PHP.valueToCode(block, 'LIST',
+  const list = Blockly.PHP.valueToCode(block, 'LIST',
       Blockly.PHP.ORDER_NONE) || '[]';
-  var code = 'array_reverse(' + list + ')';
+  const code = 'array_reverse(' + list + ')';
   return [code, Blockly.PHP.ORDER_FUNCTION_CALL];
 };
diff --git a/generators/php/logic.js b/generators/php/logic.js
index b36c3ac6d..de632f1fe 100644
--- a/generators/php/logic.js
+++ b/generators/php/logic.js
@@ -16,8 +16,8 @@ goog.require('Blockly.PHP');
 
 Blockly.PHP['controls_if'] = function(block) {
   // If/elseif/else condition.
-  var n = 0;
-  var code = '', branchCode, conditionCode;
+  let n = 0;
+  let code = '', branchCode, conditionCode;
   if (Blockly.PHP.STATEMENT_PREFIX) {
     // Automatic prefix insertion is switched off for this block.  Add manually.
     code += Blockly.PHP.injectId(Blockly.PHP.STATEMENT_PREFIX, block);
@@ -52,7 +52,7 @@ Blockly.PHP['controls_ifelse'] = Blockly.PHP['controls_if'];
 
 Blockly.PHP['logic_compare'] = function(block) {
   // Comparison operator.
-  var OPERATORS = {
+  const OPERATORS = {
     'EQ': '==',
     'NEQ': '!=',
     'LT': '<',
@@ -60,29 +60,29 @@ Blockly.PHP['logic_compare'] = function(block) {
     'GT': '>',
     'GTE': '>='
   };
-  var operator = OPERATORS[block.getFieldValue('OP')];
-  var order = (operator === '==' || operator === '!=') ?
+  const operator = OPERATORS[block.getFieldValue('OP')];
+  const order = (operator === '==' || operator === '!=') ?
       Blockly.PHP.ORDER_EQUALITY : Blockly.PHP.ORDER_RELATIONAL;
-  var argument0 = Blockly.PHP.valueToCode(block, 'A', order) || '0';
-  var argument1 = Blockly.PHP.valueToCode(block, 'B', order) || '0';
-  var code = argument0 + ' ' + operator + ' ' + argument1;
+  const argument0 = Blockly.PHP.valueToCode(block, 'A', order) || '0';
+  const argument1 = Blockly.PHP.valueToCode(block, 'B', order) || '0';
+  const code = argument0 + ' ' + operator + ' ' + argument1;
   return [code, order];
 };
 
 Blockly.PHP['logic_operation'] = function(block) {
   // Operations 'and', 'or'.
-  var operator = (block.getFieldValue('OP') === 'AND') ? '&&' : '||';
-  var order = (operator === '&&') ? Blockly.PHP.ORDER_LOGICAL_AND :
+  const operator = (block.getFieldValue('OP') === 'AND') ? '&&' : '||';
+  const order = (operator === '&&') ? Blockly.PHP.ORDER_LOGICAL_AND :
       Blockly.PHP.ORDER_LOGICAL_OR;
-  var argument0 = Blockly.PHP.valueToCode(block, 'A', order);
-  var argument1 = Blockly.PHP.valueToCode(block, 'B', order);
+  let argument0 = Blockly.PHP.valueToCode(block, 'A', order);
+  let argument1 = Blockly.PHP.valueToCode(block, 'B', order);
   if (!argument0 && !argument1) {
     // If there are no arguments, then the return value is false.
     argument0 = 'false';
     argument1 = 'false';
   } else {
     // Single missing arguments have no effect on the return value.
-    var defaultArgument = (operator === '&&') ? 'true' : 'false';
+    const defaultArgument = (operator === '&&') ? 'true' : 'false';
     if (!argument0) {
       argument0 = defaultArgument;
     }
@@ -90,22 +90,22 @@ Blockly.PHP['logic_operation'] = function(block) {
       argument1 = defaultArgument;
     }
   }
-  var code = argument0 + ' ' + operator + ' ' + argument1;
+  const code = argument0 + ' ' + operator + ' ' + argument1;
   return [code, order];
 };
 
 Blockly.PHP['logic_negate'] = function(block) {
   // Negation.
-  var order = Blockly.PHP.ORDER_LOGICAL_NOT;
-  var argument0 = Blockly.PHP.valueToCode(block, 'BOOL', order) ||
+  const order = Blockly.PHP.ORDER_LOGICAL_NOT;
+  const argument0 = Blockly.PHP.valueToCode(block, 'BOOL', order) ||
       'true';
-  var code = '!' + argument0;
+  const code = '!' + argument0;
   return [code, order];
 };
 
 Blockly.PHP['logic_boolean'] = function(block) {
   // Boolean values true and false.
-  var code = (block.getFieldValue('BOOL') === 'TRUE') ? 'true' : 'false';
+  const code = (block.getFieldValue('BOOL') === 'TRUE') ? 'true' : 'false';
   return [code, Blockly.PHP.ORDER_ATOMIC];
 };
 
@@ -116,12 +116,12 @@ Blockly.PHP['logic_null'] = function(block) {
 
 Blockly.PHP['logic_ternary'] = function(block) {
   // Ternary operator.
-  var value_if = Blockly.PHP.valueToCode(block, 'IF',
+  const value_if = Blockly.PHP.valueToCode(block, 'IF',
       Blockly.PHP.ORDER_CONDITIONAL) || 'false';
-  var value_then = Blockly.PHP.valueToCode(block, 'THEN',
+  const value_then = Blockly.PHP.valueToCode(block, 'THEN',
       Blockly.PHP.ORDER_CONDITIONAL) || 'null';
-  var value_else = Blockly.PHP.valueToCode(block, 'ELSE',
+  const value_else = Blockly.PHP.valueToCode(block, 'ELSE',
       Blockly.PHP.ORDER_CONDITIONAL) || 'null';
-  var code = value_if + ' ? ' + value_then + ' : ' + value_else;
+  const code = value_if + ' ? ' + value_then + ' : ' + value_else;
   return [code, Blockly.PHP.ORDER_CONDITIONAL];
 };
diff --git a/generators/php/loops.js b/generators/php/loops.js
index f9eb23f36..efc38f654 100644
--- a/generators/php/loops.js
+++ b/generators/php/loops.js
@@ -16,20 +16,21 @@ goog.require('Blockly.PHP');
 
 Blockly.PHP['controls_repeat_ext'] = function(block) {
   // Repeat n times.
+  let repeats;
   if (block.getField('TIMES')) {
     // Internal number.
-    var repeats = String(Number(block.getFieldValue('TIMES')));
+    repeats = String(Number(block.getFieldValue('TIMES')));
   } else {
     // External number.
-    var repeats = Blockly.PHP.valueToCode(block, 'TIMES',
+    repeats = Blockly.PHP.valueToCode(block, 'TIMES',
         Blockly.PHP.ORDER_ASSIGNMENT) || '0';
   }
-  var branch = Blockly.PHP.statementToCode(block, 'DO');
+  let branch = Blockly.PHP.statementToCode(block, 'DO');
   branch = Blockly.PHP.addLoopTrap(branch, block);
-  var code = '';
-  var loopVar = Blockly.PHP.nameDB_.getDistinctName(
+  let code = '';
+  const loopVar = Blockly.PHP.nameDB_.getDistinctName(
       'count', Blockly.VARIABLE_CATEGORY_NAME);
-  var endVar = repeats;
+  let endVar = repeats;
   if (!repeats.match(/^\w+$/) && !Blockly.isNumber(repeats)) {
     endVar = Blockly.PHP.nameDB_.getDistinctName(
         'repeat_end', Blockly.VARIABLE_CATEGORY_NAME);
@@ -46,11 +47,11 @@ Blockly.PHP['controls_repeat'] = Blockly.PHP['controls_repeat_ext'];
 
 Blockly.PHP['controls_whileUntil'] = function(block) {
   // Do while/until loop.
-  var until = block.getFieldValue('MODE') === 'UNTIL';
-  var argument0 = Blockly.PHP.valueToCode(block, 'BOOL',
+  const until = block.getFieldValue('MODE') === 'UNTIL';
+  let argument0 = Blockly.PHP.valueToCode(block, 'BOOL',
       until ? Blockly.PHP.ORDER_LOGICAL_NOT :
       Blockly.PHP.ORDER_NONE) || 'false';
-  var branch = Blockly.PHP.statementToCode(block, 'DO');
+  let branch = Blockly.PHP.statementToCode(block, 'DO');
   branch = Blockly.PHP.addLoopTrap(branch, block);
   if (until) {
     argument0 = '!' + argument0;
@@ -60,25 +61,25 @@ Blockly.PHP['controls_whileUntil'] = function(block) {
 
 Blockly.PHP['controls_for'] = function(block) {
   // For loop.
-  var variable0 = Blockly.PHP.nameDB_.getName(
+  const variable0 = Blockly.PHP.nameDB_.getName(
       block.getFieldValue('VAR'), Blockly.VARIABLE_CATEGORY_NAME);
-  var argument0 = Blockly.PHP.valueToCode(block, 'FROM',
+  const argument0 = Blockly.PHP.valueToCode(block, 'FROM',
       Blockly.PHP.ORDER_ASSIGNMENT) || '0';
-  var argument1 = Blockly.PHP.valueToCode(block, 'TO',
+  const argument1 = Blockly.PHP.valueToCode(block, 'TO',
       Blockly.PHP.ORDER_ASSIGNMENT) || '0';
-  var increment = Blockly.PHP.valueToCode(block, 'BY',
+  const increment = Blockly.PHP.valueToCode(block, 'BY',
       Blockly.PHP.ORDER_ASSIGNMENT) || '1';
-  var branch = Blockly.PHP.statementToCode(block, 'DO');
+  let branch = Blockly.PHP.statementToCode(block, 'DO');
   branch = Blockly.PHP.addLoopTrap(branch, block);
-  var code;
+  let code;
   if (Blockly.isNumber(argument0) && Blockly.isNumber(argument1) &&
       Blockly.isNumber(increment)) {
     // All arguments are simple numbers.
-    var up = Number(argument0) <= Number(argument1);
+    const up = Number(argument0) <= Number(argument1);
     code = 'for (' + variable0 + ' = ' + argument0 + '; ' +
         variable0 + (up ? ' <= ' : ' >= ') + argument1 + '; ' +
         variable0;
-    var step = Math.abs(Number(increment));
+    const step = Math.abs(Number(increment));
     if (step === 1) {
       code += up ? '++' : '--';
     } else {
@@ -88,13 +89,13 @@ Blockly.PHP['controls_for'] = function(block) {
   } else {
     code = '';
     // Cache non-trivial values to variables to prevent repeated look-ups.
-    var startVar = argument0;
+    let startVar = argument0;
     if (!argument0.match(/^\w+$/) && !Blockly.isNumber(argument0)) {
       startVar = Blockly.PHP.nameDB_.getDistinctName(
           variable0 + '_start', Blockly.VARIABLE_CATEGORY_NAME);
       code += startVar + ' = ' + argument0 + ';\n';
     }
-    var endVar = argument1;
+    let endVar = argument1;
     if (!argument1.match(/^\w+$/) && !Blockly.isNumber(argument1)) {
       endVar = Blockly.PHP.nameDB_.getDistinctName(
           variable0 + '_end', Blockly.VARIABLE_CATEGORY_NAME);
@@ -102,7 +103,7 @@ Blockly.PHP['controls_for'] = function(block) {
     }
     // Determine loop direction at start, in case one of the bounds
     // changes during loop execution.
-    var incVar = Blockly.PHP.nameDB_.getDistinctName(
+    const incVar = Blockly.PHP.nameDB_.getDistinctName(
         variable0 + '_inc', Blockly.VARIABLE_CATEGORY_NAME);
     code += incVar + ' = ';
     if (Blockly.isNumber(increment)) {
@@ -125,13 +126,13 @@ Blockly.PHP['controls_for'] = function(block) {
 
 Blockly.PHP['controls_forEach'] = function(block) {
   // For each loop.
-  var variable0 = Blockly.PHP.nameDB_.getName(
+  const variable0 = Blockly.PHP.nameDB_.getName(
       block.getFieldValue('VAR'), Blockly.VARIABLE_CATEGORY_NAME);
-  var argument0 = Blockly.PHP.valueToCode(block, 'LIST',
+  const argument0 = Blockly.PHP.valueToCode(block, 'LIST',
       Blockly.PHP.ORDER_ASSIGNMENT) || '[]';
-  var branch = Blockly.PHP.statementToCode(block, 'DO');
+  let branch = Blockly.PHP.statementToCode(block, 'DO');
   branch = Blockly.PHP.addLoopTrap(branch, block);
-  var code = '';
+  let code = '';
   code += 'foreach (' + argument0 + ' as ' + variable0 +
       ') {\n' + branch + '}\n';
   return code;
@@ -139,7 +140,7 @@ Blockly.PHP['controls_forEach'] = function(block) {
 
 Blockly.PHP['controls_flow_statements'] = function(block) {
   // Flow statements: continue, break.
-  var xfix = '';
+  let xfix = '';
   if (Blockly.PHP.STATEMENT_PREFIX) {
     // Automatic prefix insertion is switched off for this block.  Add manually.
     xfix += Blockly.PHP.injectId(Blockly.PHP.STATEMENT_PREFIX, block);
@@ -150,7 +151,7 @@ Blockly.PHP['controls_flow_statements'] = function(block) {
     xfix += Blockly.PHP.injectId(Blockly.PHP.STATEMENT_SUFFIX, block);
   }
   if (Blockly.PHP.STATEMENT_PREFIX) {
-    var loop = Blockly.Constants.Loops
+    const loop = Blockly.Constants.Loops
         .CONTROL_FLOW_IN_LOOP_CHECK_MIXIN.getSurroundLoop(block);
     if (loop && !loop.suppressPrefixSuffix) {
       // Inject loop's statement prefix here since the regular one at the end
diff --git a/generators/php/math.js b/generators/php/math.js
index 4b375b564..a442ca7ab 100644
--- a/generators/php/math.js
+++ b/generators/php/math.js
@@ -16,8 +16,8 @@ goog.require('Blockly.PHP');
 
 Blockly.PHP['math_number'] = function(block) {
   // Numeric value.
-  var code = Number(block.getFieldValue('NUM'));
-  var order = code >= 0 ? Blockly.PHP.ORDER_ATOMIC :
+  let code = Number(block.getFieldValue('NUM'));
+  const order = code >= 0 ? Blockly.PHP.ORDER_ATOMIC :
               Blockly.PHP.ORDER_UNARY_NEGATION;
   if (code === Infinity) {
     code = 'INF';
@@ -29,27 +29,27 @@ Blockly.PHP['math_number'] = function(block) {
 
 Blockly.PHP['math_arithmetic'] = function(block) {
   // Basic arithmetic operators, and power.
-  var OPERATORS = {
+  const OPERATORS = {
     'ADD': [' + ', Blockly.PHP.ORDER_ADDITION],
     'MINUS': [' - ', Blockly.PHP.ORDER_SUBTRACTION],
     'MULTIPLY': [' * ', Blockly.PHP.ORDER_MULTIPLICATION],
     'DIVIDE': [' / ', Blockly.PHP.ORDER_DIVISION],
     'POWER': [' ** ', Blockly.PHP.ORDER_POWER]
   };
-  var tuple = OPERATORS[block.getFieldValue('OP')];
-  var operator = tuple[0];
-  var order = tuple[1];
-  var argument0 = Blockly.PHP.valueToCode(block, 'A', order) || '0';
-  var argument1 = Blockly.PHP.valueToCode(block, 'B', order) || '0';
-  var code = argument0 + operator + argument1;
+  const tuple = OPERATORS[block.getFieldValue('OP')];
+  const operator = tuple[0];
+  const order = tuple[1];
+  const argument0 = Blockly.PHP.valueToCode(block, 'A', order) || '0';
+  const argument1 = Blockly.PHP.valueToCode(block, 'B', order) || '0';
+  const code = argument0 + operator + argument1;
   return [code, order];
 };
 
 Blockly.PHP['math_single'] = function(block) {
   // Math operators with single operand.
-  var operator = block.getFieldValue('OP');
-  var code;
-  var arg;
+  const operator = block.getFieldValue('OP');
+  let code;
+  let arg;
   if (operator === 'NEG') {
     // Negation is a special case given its different operator precedence.
     arg = Blockly.PHP.valueToCode(block, 'NUM',
@@ -131,7 +131,7 @@ Blockly.PHP['math_single'] = function(block) {
 
 Blockly.PHP['math_constant'] = function(block) {
   // Constants: PI, E, the Golden Ratio, sqrt(2), 1/sqrt(2), INFINITY.
-  var CONSTANTS = {
+  const CONSTANTS = {
     'PI': ['M_PI', Blockly.PHP.ORDER_ATOMIC],
     'E': ['M_E', Blockly.PHP.ORDER_ATOMIC],
     'GOLDEN_RATIO': ['(1 + sqrt(5)) / 2', Blockly.PHP.ORDER_DIVISION],
@@ -145,13 +145,13 @@ Blockly.PHP['math_constant'] = function(block) {
 Blockly.PHP['math_number_property'] = function(block) {
   // Check if a number is even, odd, prime, whole, positive, or negative
   // or if it is divisible by certain number. Returns true or false.
-  var number_to_check = Blockly.PHP.valueToCode(block, 'NUMBER_TO_CHECK',
+  const number_to_check = Blockly.PHP.valueToCode(block, 'NUMBER_TO_CHECK',
       Blockly.PHP.ORDER_MODULUS) || '0';
-  var dropdown_property = block.getFieldValue('PROPERTY');
-  var code;
+  const dropdown_property = block.getFieldValue('PROPERTY');
+  let code;
   if (dropdown_property === 'PRIME') {
     // Prime is a special case as it is not a one-liner test.
-    var functionName = Blockly.PHP.provideFunction_(
+    const functionName = Blockly.PHP.provideFunction_(
         'math_isPrime',
         ['function ' + Blockly.PHP.FUNCTION_NAME_PLACEHOLDER_ + '($n) {',
          '  // https://en.wikipedia.org/wiki/Primality_test#Naive_methods',
@@ -191,20 +191,21 @@ Blockly.PHP['math_number_property'] = function(block) {
     case 'NEGATIVE':
       code = number_to_check + ' < 0';
       break;
-    case 'DIVISIBLE_BY':
-      var divisor = Blockly.PHP.valueToCode(block, 'DIVISOR',
+    case 'DIVISIBLE_BY': {
+      const divisor = Blockly.PHP.valueToCode(block, 'DIVISOR',
           Blockly.PHP.ORDER_MODULUS) || '0';
       code = number_to_check + ' % ' + divisor + ' == 0';
       break;
+    }
   }
   return [code, Blockly.PHP.ORDER_EQUALITY];
 };
 
 Blockly.PHP['math_change'] = function(block) {
   // Add to a variable in place.
-  var argument0 = Blockly.PHP.valueToCode(block, 'DELTA',
+  const argument0 = Blockly.PHP.valueToCode(block, 'DELTA',
       Blockly.PHP.ORDER_ADDITION) || '0';
-  var varName = Blockly.PHP.nameDB_.getName(
+  const varName = Blockly.PHP.nameDB_.getName(
       block.getFieldValue('VAR'), Blockly.VARIABLE_CATEGORY_NAME);
   return varName + ' += ' + argument0 + ';\n';
 };
@@ -216,8 +217,9 @@ Blockly.PHP['math_trig'] = Blockly.PHP['math_single'];
 
 Blockly.PHP['math_on_list'] = function(block) {
   // Math functions for lists.
-  var func = block.getFieldValue('OP');
-  var list, code;
+  const func = block.getFieldValue('OP');
+  let list;
+  let code;
   switch (func) {
     case 'SUM':
       list = Blockly.PHP.valueToCode(block, 'LIST',
@@ -234,8 +236,8 @@ Blockly.PHP['math_on_list'] = function(block) {
           Blockly.PHP.ORDER_FUNCTION_CALL) || 'array()';
       code = 'max(' + list + ')';
       break;
-    case 'AVERAGE':
-      var functionName = Blockly.PHP.provideFunction_(
+    case 'AVERAGE': {
+      const functionName = Blockly.PHP.provideFunction_(
           'math_mean',
           ['function ' + Blockly.PHP.FUNCTION_NAME_PLACEHOLDER_ +
               '($myList) {',
@@ -245,8 +247,9 @@ Blockly.PHP['math_on_list'] = function(block) {
           Blockly.PHP.ORDER_NONE) || 'array()';
       code = functionName + '(' + list + ')';
       break;
-    case 'MEDIAN':
-      var functionName = Blockly.PHP.provideFunction_(
+    }
+    case 'MEDIAN': {
+      const functionName = Blockly.PHP.provideFunction_(
           'math_median',
           ['function ' + Blockly.PHP.FUNCTION_NAME_PLACEHOLDER_ +
               '($arr) {',
@@ -259,11 +262,12 @@ Blockly.PHP['math_on_list'] = function(block) {
           Blockly.PHP.ORDER_NONE) || '[]';
       code = functionName + '(' + list + ')';
       break;
-    case 'MODE':
+    }
+    case 'MODE': {
       // As a list of numbers can contain more than one mode,
       // the returned result is provided as an array.
       // Mode of [3, 'x', 'x', 1, 1, 2, '3'] -> ['x', 1].
-      var functionName = Blockly.PHP.provideFunction_(
+      const functionName = Blockly.PHP.provideFunction_(
           'math_modes',
           ['function ' + Blockly.PHP.FUNCTION_NAME_PLACEHOLDER_ +
               '($values) {',
@@ -277,8 +281,9 @@ Blockly.PHP['math_on_list'] = function(block) {
           Blockly.PHP.ORDER_NONE) || '[]';
       code = functionName + '(' + list + ')';
       break;
-    case 'STD_DEV':
-      var functionName = Blockly.PHP.provideFunction_(
+    }
+    case 'STD_DEV': {
+      const functionName = Blockly.PHP.provideFunction_(
           'math_standard_deviation',
           ['function ' + Blockly.PHP.FUNCTION_NAME_PLACEHOLDER_ +
               '($numbers) {',
@@ -293,8 +298,9 @@ Blockly.PHP['math_on_list'] = function(block) {
               Blockly.PHP.ORDER_NONE) || '[]';
       code = functionName + '(' + list + ')';
       break;
-    case 'RANDOM':
-      var functionName = Blockly.PHP.provideFunction_(
+    }
+    case 'RANDOM': {
+      const functionName = Blockly.PHP.provideFunction_(
           'math_random_list',
           ['function ' + Blockly.PHP.FUNCTION_NAME_PLACEHOLDER_ +
               '($list) {',
@@ -305,6 +311,7 @@ Blockly.PHP['math_on_list'] = function(block) {
           Blockly.PHP.ORDER_NONE) || '[]';
       code = functionName + '(' + list + ')';
       break;
+    }
     default:
       throw Error('Unknown operator: ' + func);
   }
@@ -313,34 +320,34 @@ Blockly.PHP['math_on_list'] = function(block) {
 
 Blockly.PHP['math_modulo'] = function(block) {
   // Remainder computation.
-  var argument0 = Blockly.PHP.valueToCode(block, 'DIVIDEND',
+  const argument0 = Blockly.PHP.valueToCode(block, 'DIVIDEND',
       Blockly.PHP.ORDER_MODULUS) || '0';
-  var argument1 = Blockly.PHP.valueToCode(block, 'DIVISOR',
+  const argument1 = Blockly.PHP.valueToCode(block, 'DIVISOR',
       Blockly.PHP.ORDER_MODULUS) || '0';
-  var code = argument0 + ' % ' + argument1;
+  const code = argument0 + ' % ' + argument1;
   return [code, Blockly.PHP.ORDER_MODULUS];
 };
 
 Blockly.PHP['math_constrain'] = function(block) {
   // Constrain a number between two limits.
-  var argument0 = Blockly.PHP.valueToCode(block, 'VALUE',
+  const argument0 = Blockly.PHP.valueToCode(block, 'VALUE',
       Blockly.PHP.ORDER_NONE) || '0';
-  var argument1 = Blockly.PHP.valueToCode(block, 'LOW',
+  const argument1 = Blockly.PHP.valueToCode(block, 'LOW',
       Blockly.PHP.ORDER_NONE) || '0';
-  var argument2 = Blockly.PHP.valueToCode(block, 'HIGH',
+  const argument2 = Blockly.PHP.valueToCode(block, 'HIGH',
       Blockly.PHP.ORDER_NONE) || 'Infinity';
-  var code = 'min(max(' + argument0 + ', ' + argument1 + '), ' +
+  const code = 'min(max(' + argument0 + ', ' + argument1 + '), ' +
       argument2 + ')';
   return [code, Blockly.PHP.ORDER_FUNCTION_CALL];
 };
 
 Blockly.PHP['math_random_int'] = function(block) {
   // Random integer between [X] and [Y].
-  var argument0 = Blockly.PHP.valueToCode(block, 'FROM',
+  const argument0 = Blockly.PHP.valueToCode(block, 'FROM',
       Blockly.PHP.ORDER_NONE) || '0';
-  var argument1 = Blockly.PHP.valueToCode(block, 'TO',
+  const argument1 = Blockly.PHP.valueToCode(block, 'TO',
       Blockly.PHP.ORDER_NONE) || '0';
-  var functionName = Blockly.PHP.provideFunction_(
+  const functionName = Blockly.PHP.provideFunction_(
       'math_random_int',
       ['function ' + Blockly.PHP.FUNCTION_NAME_PLACEHOLDER_ +
           '($a, $b) {',
@@ -349,7 +356,7 @@ Blockly.PHP['math_random_int'] = function(block) {
        '  }',
        '  return rand($a, $b);',
        '}']);
-  var code = functionName + '(' + argument0 + ', ' + argument1 + ')';
+  const code = functionName + '(' + argument0 + ', ' + argument1 + ')';
   return [code, Blockly.PHP.ORDER_FUNCTION_CALL];
 };
 
@@ -360,9 +367,9 @@ Blockly.PHP['math_random_float'] = function(block) {
 
 Blockly.PHP['math_atan2'] = function(block) {
   // Arctangent of point (X, Y) in degrees from -180 to 180.
-  var argument0 = Blockly.PHP.valueToCode(block, 'X',
+  const argument0 = Blockly.PHP.valueToCode(block, 'X',
       Blockly.PHP.ORDER_NONE) || '0';
-  var argument1 = Blockly.PHP.valueToCode(block, 'Y',
+  const argument1 = Blockly.PHP.valueToCode(block, 'Y',
       Blockly.PHP.ORDER_NONE) || '0';
   return ['atan2(' + argument1 + ', ' + argument0 + ') / pi() * 180',
       Blockly.PHP.ORDER_DIVISION];
diff --git a/generators/php/procedures.js b/generators/php/procedures.js
index 6002dbe87..9b7ab47d6 100644
--- a/generators/php/procedures.js
+++ b/generators/php/procedures.js
@@ -18,28 +18,28 @@ Blockly.PHP['procedures_defreturn'] = function(block) {
   // Define a procedure with a return value.
   // First, add a 'global' statement for every variable that is not shadowed by
   // a local parameter.
-  var globals = [];
-  var workspace = block.workspace;
-  var variables = Blockly.Variables.allUsedVarModels(workspace) || [];
-  for (var i = 0, variable; variable = variables[i]; i++) {
-    var varName = variable.name;
+  const globals = [];
+  const workspace = block.workspace;
+  const usedVariables = Blockly.Variables.allUsedVarModels(workspace) || [];
+  for (let i = 0, variable; variable = usedVariables[i]; i++) {
+    const varName = variable.name;
     if (block.getVars().indexOf(varName) === -1) {
       globals.push(Blockly.PHP.nameDB_.getName(varName,
           Blockly.VARIABLE_CATEGORY_NAME));
     }
   }
   // Add developer variables.
-  var devVarList = Blockly.Variables.allDeveloperVariables(workspace);
-  for (var i = 0; i < devVarList.length; i++) {
+  const devVarList = Blockly.Variables.allDeveloperVariables(workspace);
+  for (let i = 0; i < devVarList.length; i++) {
     globals.push(Blockly.PHP.nameDB_.getName(devVarList[i],
         Blockly.Names.DEVELOPER_VARIABLE_TYPE));
   }
-  globals = globals.length ?
+  const globalStr = globals.length ?
       Blockly.PHP.INDENT + 'global ' + globals.join(', ') + ';\n' : '';
 
-  var funcName = Blockly.PHP.nameDB_.getName(
+  const funcName = Blockly.PHP.nameDB_.getName(
       block.getFieldValue('NAME'), Blockly.PROCEDURE_CATEGORY_NAME);
-  var xfix1 = '';
+  let xfix1 = '';
   if (Blockly.PHP.STATEMENT_PREFIX) {
     xfix1 += Blockly.PHP.injectId(Blockly.PHP.STATEMENT_PREFIX, block);
   }
@@ -49,16 +49,16 @@ Blockly.PHP['procedures_defreturn'] = function(block) {
   if (xfix1) {
     xfix1 = Blockly.PHP.prefixLines(xfix1, Blockly.PHP.INDENT);
   }
-  var loopTrap = '';
+  let loopTrap = '';
   if (Blockly.PHP.INFINITE_LOOP_TRAP) {
     loopTrap = Blockly.PHP.prefixLines(
         Blockly.PHP.injectId(Blockly.PHP.INFINITE_LOOP_TRAP, block),
         Blockly.PHP.INDENT);
   }
-  var branch = Blockly.PHP.statementToCode(block, 'STACK');
-  var returnValue = Blockly.PHP.valueToCode(block, 'RETURN',
+  const branch = Blockly.PHP.statementToCode(block, 'STACK');
+  let returnValue = Blockly.PHP.valueToCode(block, 'RETURN',
       Blockly.PHP.ORDER_NONE) || '';
-  var xfix2 = '';
+  let xfix2 = '';
   if (branch && returnValue) {
     // After executing the function body, revisit this block for the return.
     xfix2 = xfix1;
@@ -66,14 +66,14 @@ Blockly.PHP['procedures_defreturn'] = function(block) {
   if (returnValue) {
     returnValue = Blockly.PHP.INDENT + 'return ' + returnValue + ';\n';
   }
-  var args = [];
-  var variables = block.getVars();
-  for (var i = 0; i < variables.length; i++) {
+  const args = [];
+  const variables = block.getVars();
+  for (let i = 0; i < variables.length; i++) {
     args[i] = Blockly.PHP.nameDB_.getName(variables[i],
         Blockly.VARIABLE_CATEGORY_NAME);
   }
-  var code = 'function ' + funcName + '(' + args.join(', ') + ') {\n' +
-      globals + xfix1 + loopTrap + branch + xfix2 + returnValue + '}';
+  let code = 'function ' + funcName + '(' + args.join(', ') + ') {\n' +
+      globalStr + xfix1 + loopTrap + branch + xfix2 + returnValue + '}';
   code = Blockly.PHP.scrub_(block, code);
   // Add % so as not to collide with helper functions in definitions list.
   Blockly.PHP.definitions_['%' + funcName] = code;
@@ -87,15 +87,15 @@ Blockly.PHP['procedures_defnoreturn'] =
 
 Blockly.PHP['procedures_callreturn'] = function(block) {
   // Call a procedure with a return value.
-  var funcName = Blockly.PHP.nameDB_.getName(
+  const funcName = Blockly.PHP.nameDB_.getName(
       block.getFieldValue('NAME'), Blockly.PROCEDURE_CATEGORY_NAME);
-  var args = [];
-  var variables = block.getVars();
-  for (var i = 0; i < variables.length; i++) {
+  const args = [];
+  const variables = block.getVars();
+  for (let i = 0; i < variables.length; i++) {
     args[i] = Blockly.PHP.valueToCode(block, 'ARG' + i,
         Blockly.PHP.ORDER_NONE) || 'null';
   }
-  var code = funcName + '(' + args.join(', ') + ')';
+  const code = funcName + '(' + args.join(', ') + ')';
   return [code, Blockly.PHP.ORDER_FUNCTION_CALL];
 };
 
@@ -103,15 +103,15 @@ Blockly.PHP['procedures_callnoreturn'] = function(block) {
   // Call a procedure with no return value.
   // Generated code is for a function call as a statement is the same as a
   // function call as a value, with the addition of line ending.
-  var tuple = Blockly.PHP['procedures_callreturn'](block);
+  const tuple = Blockly.PHP['procedures_callreturn'](block);
   return tuple[0] + ';\n';
 };
 
 Blockly.PHP['procedures_ifreturn'] = function(block) {
   // Conditionally return value from a procedure.
-  var condition = Blockly.PHP.valueToCode(block, 'CONDITION',
+  const condition = Blockly.PHP.valueToCode(block, 'CONDITION',
       Blockly.PHP.ORDER_NONE) || 'false';
-  var code = 'if (' + condition + ') {\n';
+  let code = 'if (' + condition + ') {\n';
   if (Blockly.PHP.STATEMENT_SUFFIX) {
     // Inject any statement suffix here since the regular one at the end
     // will not get executed if the return is triggered.
@@ -120,7 +120,7 @@ Blockly.PHP['procedures_ifreturn'] = function(block) {
         Blockly.PHP.INDENT);
   }
   if (block.hasReturnValue_) {
-    var value = Blockly.PHP.valueToCode(block, 'VALUE',
+    const value = Blockly.PHP.valueToCode(block, 'VALUE',
         Blockly.PHP.ORDER_NONE) || 'null';
     code += Blockly.PHP.INDENT + 'return ' + value + ';\n';
   } else {
diff --git a/generators/php/text.js b/generators/php/text.js
index cb71706cf..08fde44de 100644
--- a/generators/php/text.js
+++ b/generators/php/text.js
@@ -16,14 +16,14 @@ goog.require('Blockly.PHP');
 
 Blockly.PHP['text'] = function(block) {
   // Text value.
-  var code = Blockly.PHP.quote_(block.getFieldValue('TEXT'));
+  const code = Blockly.PHP.quote_(block.getFieldValue('TEXT'));
   return [code, Blockly.PHP.ORDER_ATOMIC];
 };
 
 Blockly.PHP['text_multiline'] = function(block) {
   // Text value.
-  var code = Blockly.PHP.multiline_quote_(block.getFieldValue('TEXT'));
-  var order = code.indexOf('.') !== -1 ? Blockly.PHP.ORDER_STRING_CONCAT :
+  const code = Blockly.PHP.multiline_quote_(block.getFieldValue('TEXT'));
+  const order = code.indexOf('.') !== -1 ? Blockly.PHP.ORDER_STRING_CONCAT :
       Blockly.PHP.ORDER_ATOMIC;
   return [code, order];
 };
@@ -33,40 +33,40 @@ Blockly.PHP['text_join'] = function(block) {
   if (block.itemCount_ === 0) {
     return ['\'\'', Blockly.PHP.ORDER_ATOMIC];
   } else if (block.itemCount_ === 1) {
-    var element = Blockly.PHP.valueToCode(block, 'ADD0',
+    const element = Blockly.PHP.valueToCode(block, 'ADD0',
         Blockly.PHP.ORDER_NONE) || '\'\'';
-    var code = element;
+    const code = element;
     return [code, Blockly.PHP.ORDER_NONE];
   } else if (block.itemCount_ === 2) {
-    var element0 = Blockly.PHP.valueToCode(block, 'ADD0',
+    const element0 = Blockly.PHP.valueToCode(block, 'ADD0',
         Blockly.PHP.ORDER_STRING_CONCAT) || '\'\'';
-    var element1 = Blockly.PHP.valueToCode(block, 'ADD1',
+    const element1 = Blockly.PHP.valueToCode(block, 'ADD1',
         Blockly.PHP.ORDER_STRING_CONCAT) || '\'\'';
-    var code = element0 + ' . ' + element1;
+    const code = element0 + ' . ' + element1;
     return [code, Blockly.PHP.ORDER_STRING_CONCAT];
   } else {
-    var elements = new Array(block.itemCount_);
-    for (var i = 0; i < block.itemCount_; i++) {
+    const elements = new Array(block.itemCount_);
+    for (let i = 0; i < block.itemCount_; i++) {
       elements[i] = Blockly.PHP.valueToCode(block, 'ADD' + i,
           Blockly.PHP.ORDER_NONE) || '\'\'';
     }
-    var code = 'implode(\'\', array(' + elements.join(',') + '))';
+    const code = 'implode(\'\', array(' + elements.join(',') + '))';
     return [code, Blockly.PHP.ORDER_FUNCTION_CALL];
   }
 };
 
 Blockly.PHP['text_append'] = function(block) {
   // Append to a variable in place.
-  var varName = Blockly.PHP.nameDB_.getName(
+  const varName = Blockly.PHP.nameDB_.getName(
       block.getFieldValue('VAR'), Blockly.VARIABLE_CATEGORY_NAME);
-  var value = Blockly.PHP.valueToCode(block, 'TEXT',
+  const value = Blockly.PHP.valueToCode(block, 'TEXT',
       Blockly.PHP.ORDER_ASSIGNMENT) || '\'\'';
   return varName + ' .= ' + value + ';\n';
 };
 
 Blockly.PHP['text_length'] = function(block) {
   // String or array length.
-  var functionName = Blockly.PHP.provideFunction_(
+  const functionName = Blockly.PHP.provideFunction_(
       'length',
       ['function ' + Blockly.PHP.FUNCTION_NAME_PLACEHOLDER_ + '($value) {',
        '  if (is_string($value)) {',
@@ -75,34 +75,33 @@ Blockly.PHP['text_length'] = function(block) {
        '    return count($value);',
        '  }',
        '}']);
-  var text = Blockly.PHP.valueToCode(block, 'VALUE',
+  const text = Blockly.PHP.valueToCode(block, 'VALUE',
       Blockly.PHP.ORDER_NONE) || '\'\'';
   return [functionName + '(' + text + ')', Blockly.PHP.ORDER_FUNCTION_CALL];
 };
 
 Blockly.PHP['text_isEmpty'] = function(block) {
   // Is the string null or array empty?
-  var text = Blockly.PHP.valueToCode(block, 'VALUE',
+  const text = Blockly.PHP.valueToCode(block, 'VALUE',
       Blockly.PHP.ORDER_NONE) || '\'\'';
   return ['empty(' + text + ')', Blockly.PHP.ORDER_FUNCTION_CALL];
 };
 
 Blockly.PHP['text_indexOf'] = function(block) {
   // Search the text for a substring.
-  var operator = block.getFieldValue('END') === 'FIRST' ?
+  const operator = block.getFieldValue('END') === 'FIRST' ?
       'strpos' : 'strrpos';
-  var substring = Blockly.PHP.valueToCode(block, 'FIND',
+  const substring = Blockly.PHP.valueToCode(block, 'FIND',
       Blockly.PHP.ORDER_NONE) || '\'\'';
-  var text = Blockly.PHP.valueToCode(block, 'VALUE',
+  const text = Blockly.PHP.valueToCode(block, 'VALUE',
       Blockly.PHP.ORDER_NONE) || '\'\'';
+  let errorIndex = ' -1';
+  let indexAdjustment = '';
   if (block.workspace.options.oneBasedIndex) {
-    var errorIndex = ' 0';
-    var indexAdjustment = ' + 1';
-  } else {
-    var errorIndex = ' -1';
-    var indexAdjustment = '';
+    errorIndex = ' 0';
+    indexAdjustment = ' + 1';
   }
-  var functionName = Blockly.PHP.provideFunction_(
+  const functionName = Blockly.PHP.provideFunction_(
       block.getFieldValue('END') === 'FIRST' ?
           'text_indexOf' : 'text_lastIndexOf',
       ['function ' + Blockly.PHP.FUNCTION_NAME_PLACEHOLDER_ +
@@ -111,56 +110,61 @@ Blockly.PHP['text_indexOf'] = function(block) {
        '  return $pos === false ? ' + errorIndex + ' : $pos' +
           indexAdjustment + ';',
        '}']);
-  var code = functionName + '(' + text + ', ' + substring + ')';
+  const code = functionName + '(' + text + ', ' + substring + ')';
   return [code, Blockly.PHP.ORDER_FUNCTION_CALL];
 };
 
 Blockly.PHP['text_charAt'] = function(block) {
   // Get letter at index.
-  var where = block.getFieldValue('WHERE') || 'FROM_START';
-  var textOrder = (where === 'RANDOM') ? Blockly.PHP.ORDER_NONE :
+  const where = block.getFieldValue('WHERE') || 'FROM_START';
+  const textOrder = (where === 'RANDOM') ? Blockly.PHP.ORDER_NONE :
       Blockly.PHP.ORDER_NONE;
-  var text = Blockly.PHP.valueToCode(block, 'VALUE', textOrder) || '\'\'';
+  const text = Blockly.PHP.valueToCode(block, 'VALUE', textOrder) || '\'\'';
   switch (where) {
-    case 'FIRST':
-      var code = 'substr(' + text + ', 0, 1)';
+    case 'FIRST': {
+      const code = 'substr(' + text + ', 0, 1)';
       return [code, Blockly.PHP.ORDER_FUNCTION_CALL];
-    case 'LAST':
-      var code = 'substr(' + text + ', -1)';
+    }
+    case 'LAST': {
+      const code = 'substr(' + text + ', -1)';
       return [code, Blockly.PHP.ORDER_FUNCTION_CALL];
-    case 'FROM_START':
-      var at = Blockly.PHP.getAdjusted(block, 'AT');
-      var code = 'substr(' + text + ', ' + at + ', 1)';
+    }
+    case 'FROM_START': {
+      const at = Blockly.PHP.getAdjusted(block, 'AT');
+      const code = 'substr(' + text + ', ' + at + ', 1)';
       return [code, Blockly.PHP.ORDER_FUNCTION_CALL];
-    case 'FROM_END':
-      var at = Blockly.PHP.getAdjusted(block, 'AT', 1, true);
-      var code = 'substr(' + text + ', ' + at + ', 1)';
+    }
+    case 'FROM_END': {
+      const at = Blockly.PHP.getAdjusted(block, 'AT', 1, true);
+      const code = 'substr(' + text + ', ' + at + ', 1)';
       return [code, Blockly.PHP.ORDER_FUNCTION_CALL];
-    case 'RANDOM':
-      var functionName = Blockly.PHP.provideFunction_(
+    }
+    case 'RANDOM': {
+      const functionName = Blockly.PHP.provideFunction_(
           'text_random_letter',
           ['function ' + Blockly.PHP.FUNCTION_NAME_PLACEHOLDER_ + '($text) {',
            '  return $text[rand(0, strlen($text) - 1)];',
            '}']);
-      code = functionName + '(' + text + ')';
+      const code = functionName + '(' + text + ')';
       return [code, Blockly.PHP.ORDER_FUNCTION_CALL];
+    }
   }
   throw Error('Unhandled option (text_charAt).');
 };
 
 Blockly.PHP['text_getSubstring'] = function(block) {
   // Get substring.
-  var where1 = block.getFieldValue('WHERE1');
-  var where2 = block.getFieldValue('WHERE2');
-  var text = Blockly.PHP.valueToCode(block, 'STRING',
+  const where1 = block.getFieldValue('WHERE1');
+  const where2 = block.getFieldValue('WHERE2');
+  const text = Blockly.PHP.valueToCode(block, 'STRING',
       Blockly.PHP.ORDER_NONE) || '\'\'';
   if (where1 === 'FIRST' && where2 === 'LAST') {
-    var code = text;
+    const code = text;
     return [code, Blockly.PHP.ORDER_NONE];
   } else {
-    var at1 = Blockly.PHP.getAdjusted(block, 'AT1');
-    var at2 = Blockly.PHP.getAdjusted(block, 'AT2');
-    var functionName = Blockly.PHP.provideFunction_(
+    const at1 = Blockly.PHP.getAdjusted(block, 'AT1');
+    const at2 = Blockly.PHP.getAdjusted(block, 'AT2');
+    const functionName = Blockly.PHP.provideFunction_(
         'text_get_substring',
         ['function ' + Blockly.PHP.FUNCTION_NAME_PLACEHOLDER_ +
             '($text, $where1, $at1, $where2, $at2) {',
@@ -183,7 +187,7 @@ Blockly.PHP['text_getSubstring'] = function(block) {
          '  }',
          '  return substr($text, $at1, $length);',
          '}']);
-    var code = functionName + '(' + text + ', \'' +
+    const code = functionName + '(' + text + ', \'' +
         where1 + '\', ' + at1 + ', \'' + where2 + '\', ' + at2 + ')';
     return [code, Blockly.PHP.ORDER_FUNCTION_CALL];
   }
@@ -191,50 +195,52 @@ Blockly.PHP['text_getSubstring'] = function(block) {
 
 Blockly.PHP['text_changeCase'] = function(block) {
   // Change capitalization.
-  var text = Blockly.PHP.valueToCode(block, 'TEXT',
+  const text = Blockly.PHP.valueToCode(block, 'TEXT',
           Blockly.PHP.ORDER_NONE) || '\'\'';
+  let code;
   if (block.getFieldValue('CASE') === 'UPPERCASE') {
-    var code = 'strtoupper(' + text + ')';
+    code = 'strtoupper(' + text + ')';
   } else if (block.getFieldValue('CASE') === 'LOWERCASE') {
-    var code = 'strtolower(' + text + ')';
+    code = 'strtolower(' + text + ')';
   } else if (block.getFieldValue('CASE') === 'TITLECASE') {
-    var code = 'ucwords(strtolower(' + text + '))';
+    code = 'ucwords(strtolower(' + text + '))';
   }
   return [code, Blockly.PHP.ORDER_FUNCTION_CALL];
 };
 
 Blockly.PHP['text_trim'] = function(block) {
   // Trim spaces.
-  var OPERATORS = {
+  const OPERATORS = {
     'LEFT': 'ltrim',
     'RIGHT': 'rtrim',
     'BOTH': 'trim'
   };
-  var operator = OPERATORS[block.getFieldValue('MODE')];
-  var text = Blockly.PHP.valueToCode(block, 'TEXT',
+  const operator = OPERATORS[block.getFieldValue('MODE')];
+  const text = Blockly.PHP.valueToCode(block, 'TEXT',
       Blockly.PHP.ORDER_NONE) || '\'\'';
   return [operator + '(' + text + ')', Blockly.PHP.ORDER_FUNCTION_CALL];
 };
 
 Blockly.PHP['text_print'] = function(block) {
   // Print statement.
-  var msg = Blockly.PHP.valueToCode(block, 'TEXT',
+  const msg = Blockly.PHP.valueToCode(block, 'TEXT',
       Blockly.PHP.ORDER_NONE) || '\'\'';
   return 'print(' + msg + ');\n';
 };
 
 Blockly.PHP['text_prompt_ext'] = function(block) {
   // Prompt function.
+  let msg;
   if (block.getField('TEXT')) {
     // Internal message.
-    var msg = Blockly.PHP.quote_(block.getFieldValue('TEXT'));
+    msg = Blockly.PHP.quote_(block.getFieldValue('TEXT'));
   } else {
     // External message.
-    var msg = Blockly.PHP.valueToCode(block, 'TEXT',
+    msg = Blockly.PHP.valueToCode(block, 'TEXT',
         Blockly.PHP.ORDER_NONE) || '\'\'';
   }
-  var code = 'readline(' + msg + ')';
-  var toNumber = block.getFieldValue('TYPE') === 'NUMBER';
+  let code = 'readline(' + msg + ')';
+  const toNumber = block.getFieldValue('TYPE') === 'NUMBER';
   if (toNumber) {
     code = 'floatval(' + code + ')';
   }
@@ -244,30 +250,30 @@ Blockly.PHP['text_prompt_ext'] = function(block) {
 Blockly.PHP['text_prompt'] = Blockly.PHP['text_prompt_ext'];
 
 Blockly.PHP['text_count'] = function(block) {
-  var text = Blockly.PHP.valueToCode(block, 'TEXT',
+  const text = Blockly.PHP.valueToCode(block, 'TEXT',
       Blockly.PHP.ORDER_NONE) || '\'\'';
-  var sub = Blockly.PHP.valueToCode(block, 'SUB',
+  const sub = Blockly.PHP.valueToCode(block, 'SUB',
       Blockly.PHP.ORDER_NONE) || '\'\'';
-  var code = 'strlen(' + sub + ') === 0'
+  const code = 'strlen(' + sub + ') === 0'
     + ' ? strlen(' + text + ') + 1'
     + ' : substr_count(' + text + ', ' + sub + ')';
   return [code, Blockly.PHP.ORDER_CONDITIONAL];
 };
 
 Blockly.PHP['text_replace'] = function(block) {
-  var text = Blockly.PHP.valueToCode(block, 'TEXT',
+  const text = Blockly.PHP.valueToCode(block, 'TEXT',
       Blockly.PHP.ORDER_NONE) || '\'\'';
-  var from = Blockly.PHP.valueToCode(block, 'FROM',
+  const from = Blockly.PHP.valueToCode(block, 'FROM',
       Blockly.PHP.ORDER_NONE) || '\'\'';
-  var to = Blockly.PHP.valueToCode(block, 'TO',
+  const to = Blockly.PHP.valueToCode(block, 'TO',
       Blockly.PHP.ORDER_NONE) || '\'\'';
-  var code = 'str_replace(' + from + ', ' + to + ', ' + text + ')';
+  const code = 'str_replace(' + from + ', ' + to + ', ' + text + ')';
   return [code, Blockly.PHP.ORDER_FUNCTION_CALL];
 };
 
 Blockly.PHP['text_reverse'] = function(block) {
-  var text = Blockly.PHP.valueToCode(block, 'TEXT',
+  const text = Blockly.PHP.valueToCode(block, 'TEXT',
       Blockly.PHP.ORDER_NONE) || '\'\'';
-  var code = 'strrev(' + text + ')';
+  const code = 'strrev(' + text + ')';
   return [code, Blockly.PHP.ORDER_FUNCTION_CALL];
 };
diff --git a/generators/php/variables.js b/generators/php/variables.js
index 84f260b14..b1c19f689 100644
--- a/generators/php/variables.js
+++ b/generators/php/variables.js
@@ -16,16 +16,16 @@ goog.require('Blockly.PHP');
 
 Blockly.PHP['variables_get'] = function(block) {
     // Variable getter.
-    var code = Blockly.PHP.nameDB_.getName(block.getFieldValue('VAR'),
+    const code = Blockly.PHP.nameDB_.getName(block.getFieldValue('VAR'),
         Blockly.VARIABLE_CATEGORY_NAME);
     return [code, Blockly.PHP.ORDER_ATOMIC];
 };
 
 Blockly.PHP['variables_set'] = function(block) {
     // Variable setter.
-    var argument0 = Blockly.PHP.valueToCode(block, 'VALUE',
+    const argument0 = Blockly.PHP.valueToCode(block, 'VALUE',
             Blockly.PHP.ORDER_ASSIGNMENT) || '0';
-    var varName = Blockly.PHP.nameDB_.getName(
+    const varName = Blockly.PHP.nameDB_.getName(
         block.getFieldValue('VAR'), Blockly.VARIABLE_CATEGORY_NAME);
     return varName + ' = ' + argument0 + ';\n';
 };
diff --git a/tests/deps.mocha.js b/tests/deps.mocha.js
index 88800de2c..26fe5538f 100644
--- a/tests/deps.mocha.js
+++ b/tests/deps.mocha.js
@@ -292,14 +292,14 @@ goog.addDependency('../../generators/lua/text.js', ['Blockly.Lua.texts'], ['Bloc
 goog.addDependency('../../generators/lua/variables.js', ['Blockly.Lua.variables'], ['Blockly.Lua']);
 goog.addDependency('../../generators/lua/variables_dynamic.js', ['Blockly.Lua.variablesDynamic'], ['Blockly.Lua', 'Blockly.Lua.variables']);
 goog.addDependency('../../generators/php.js', ['Blockly.PHP'], ['Blockly.Generator', 'Blockly.inputTypes', 'Blockly.utils.object', 'Blockly.utils.string'], {'lang': 'es6'});
-goog.addDependency('../../generators/php/colour.js', ['Blockly.PHP.colour'], ['Blockly.PHP']);
-goog.addDependency('../../generators/php/lists.js', ['Blockly.PHP.lists'], ['Blockly.PHP']);
-goog.addDependency('../../generators/php/logic.js', ['Blockly.PHP.logic'], ['Blockly.PHP']);
-goog.addDependency('../../generators/php/loops.js', ['Blockly.PHP.loops'], ['Blockly.PHP']);
-goog.addDependency('../../generators/php/math.js', ['Blockly.PHP.math'], ['Blockly.PHP']);
-goog.addDependency('../../generators/php/procedures.js', ['Blockly.PHP.procedures'], ['Blockly.PHP']);
-goog.addDependency('../../generators/php/text.js', ['Blockly.PHP.texts'], ['Blockly.PHP']);
-goog.addDependency('../../generators/php/variables.js', ['Blockly.PHP.variables'], ['Blockly.PHP']);
+goog.addDependency('../../generators/php/colour.js', ['Blockly.PHP.colour'], ['Blockly.PHP'], {'lang': 'es6'});
+goog.addDependency('../../generators/php/lists.js', ['Blockly.PHP.lists'], ['Blockly.PHP'], {'lang': 'es6'});
+goog.addDependency('../../generators/php/logic.js', ['Blockly.PHP.logic'], ['Blockly.PHP'], {'lang': 'es6'});
+goog.addDependency('../../generators/php/loops.js', ['Blockly.PHP.loops'], ['Blockly.PHP'], {'lang': 'es6'});
+goog.addDependency('../../generators/php/math.js', ['Blockly.PHP.math'], ['Blockly.PHP'], {'lang': 'es6'});
+goog.addDependency('../../generators/php/procedures.js', ['Blockly.PHP.procedures'], ['Blockly.PHP'], {'lang': 'es6'});
+goog.addDependency('../../generators/php/text.js', ['Blockly.PHP.texts'], ['Blockly.PHP'], {'lang': 'es6'});
+goog.addDependency('../../generators/php/variables.js', ['Blockly.PHP.variables'], ['Blockly.PHP'], {'lang': 'es6'});
 goog.addDependency('../../generators/php/variables_dynamic.js', ['Blockly.PHP.variablesDynamic'], ['Blockly.PHP', 'Blockly.PHP.variables']);
 goog.addDependency('../../generators/python.js', ['Blockly.Python'], ['Blockly.Generator', 'Blockly.inputTypes', 'Blockly.utils.string'], {'lang': 'es6'});
 goog.addDependency('../../generators/python/colour.js', ['Blockly.Python.colour'], ['Blockly.Python'], {'lang': 'es6'});