From 3746688ebd680ce1856202a3304aaa8892c6205e Mon Sep 17 00:00:00 2001
From: Rachel Fenichel <fenichel@google.com>
Date: Fri, 5 Nov 2021 09:57:59 -0700
Subject: [PATCH] chore: update lua block generators to const and let (#5662)

---
 generators/lua/colour.js     |  24 +++---
 generators/lua/lists.js      | 122 ++++++++++++++--------------
 generators/lua/logic.js      |  46 +++++------
 generators/lua/loops.js      |  47 +++++------
 generators/lua/math.js       |  74 ++++++++---------
 generators/lua/procedures.js |  38 ++++-----
 generators/lua/text.js       | 150 ++++++++++++++++++-----------------
 generators/lua/variables.js  |   6 +-
 tests/deps.mocha.js          |  16 ++--
 9 files changed, 267 insertions(+), 256 deletions(-)

diff --git a/generators/lua/colour.js b/generators/lua/colour.js
index aefc3818f..996497036 100644
--- a/generators/lua/colour.js
+++ b/generators/lua/colour.js
@@ -16,19 +16,19 @@ goog.require('Blockly.Lua');
 
 Blockly.Lua['colour_picker'] = function(block) {
   // Colour picker.
-  var code = Blockly.Lua.quote_(block.getFieldValue('COLOUR'));
+  const code = Blockly.Lua.quote_(block.getFieldValue('COLOUR'));
   return [code, Blockly.Lua.ORDER_ATOMIC];
 };
 
 Blockly.Lua['colour_random'] = function(block) {
   // Generate a random colour.
-  var code = 'string.format("#%06x", math.random(0, 2^24 - 1))';
+  const code = 'string.format("#%06x", math.random(0, 2^24 - 1))';
   return [code, Blockly.Lua.ORDER_HIGH];
 };
 
 Blockly.Lua['colour_rgb'] = function(block) {
   // Compose a colour from RGB components expressed as percentages.
-  var functionName = Blockly.Lua.provideFunction_(
+  const functionName = Blockly.Lua.provideFunction_(
       'colour_rgb',
       ['function ' + Blockly.Lua.FUNCTION_NAME_PLACEHOLDER_ + '(r, g, b)',
        '  r = math.floor(math.min(100, math.max(0, r)) * 2.55 + .5)',
@@ -36,19 +36,19 @@ Blockly.Lua['colour_rgb'] = function(block) {
        '  b = math.floor(math.min(100, math.max(0, b)) * 2.55 + .5)',
        '  return string.format("#%02x%02x%02x", r, g, b)',
        'end']);
-  var r = Blockly.Lua.valueToCode(block, 'RED',
+  const r = Blockly.Lua.valueToCode(block, 'RED',
       Blockly.Lua.ORDER_NONE) || 0;
-  var g = Blockly.Lua.valueToCode(block, 'GREEN',
+  const g = Blockly.Lua.valueToCode(block, 'GREEN',
       Blockly.Lua.ORDER_NONE) || 0;
-  var b = Blockly.Lua.valueToCode(block, 'BLUE',
+  const b = Blockly.Lua.valueToCode(block, 'BLUE',
       Blockly.Lua.ORDER_NONE) || 0;
-  var code = functionName + '(' + r + ', ' + g + ', ' + b + ')';
+  const code = functionName + '(' + r + ', ' + g + ', ' + b + ')';
   return [code, Blockly.Lua.ORDER_HIGH];
 };
 
 Blockly.Lua['colour_blend'] = function(block) {
   // Blend two colours together.
-  var functionName = Blockly.Lua.provideFunction_(
+  const functionName = Blockly.Lua.provideFunction_(
       'colour_blend',
       ['function ' + Blockly.Lua.FUNCTION_NAME_PLACEHOLDER_ +
            '(colour1, colour2, ratio)',
@@ -64,12 +64,12 @@ Blockly.Lua['colour_blend'] = function(block) {
        '  local b = math.floor(b1 * (1 - ratio) + b2 * ratio + .5)',
        '  return string.format("#%02x%02x%02x", r, g, b)',
        'end']);
-  var colour1 = Blockly.Lua.valueToCode(block, 'COLOUR1',
+  const colour1 = Blockly.Lua.valueToCode(block, 'COLOUR1',
       Blockly.Lua.ORDER_NONE) || '\'#000000\'';
-  var colour2 = Blockly.Lua.valueToCode(block, 'COLOUR2',
+  const colour2 = Blockly.Lua.valueToCode(block, 'COLOUR2',
       Blockly.Lua.ORDER_NONE) || '\'#000000\'';
-  var ratio = Blockly.Lua.valueToCode(block, 'RATIO',
+  const ratio = Blockly.Lua.valueToCode(block, 'RATIO',
       Blockly.Lua.ORDER_NONE) || 0;
-  var code = functionName + '(' + colour1 + ', ' + colour2 + ', ' + ratio + ')';
+  const code = functionName + '(' + colour1 + ', ' + colour2 + ', ' + ratio + ')';
   return [code, Blockly.Lua.ORDER_HIGH];
 };
diff --git a/generators/lua/lists.js b/generators/lua/lists.js
index aca5c339e..3c16c75a0 100644
--- a/generators/lua/lists.js
+++ b/generators/lua/lists.js
@@ -21,18 +21,18 @@ Blockly.Lua['lists_create_empty'] = function(block) {
 
 Blockly.Lua['lists_create_with'] = function(block) {
   // Create a list with any number of elements of any type.
-  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.Lua.valueToCode(block, 'ADD' + i,
         Blockly.Lua.ORDER_NONE) || 'None';
   }
-  var code = '{' + elements.join(', ') + '}';
+  const code = '{' + elements.join(', ') + '}';
   return [code, Blockly.Lua.ORDER_HIGH];
 };
 
 Blockly.Lua['lists_repeat'] = function(block) {
   // Create a list with one element repeated.
-  var functionName = Blockly.Lua.provideFunction_(
+  const functionName = Blockly.Lua.provideFunction_(
       'create_list_repeated',
       ['function ' + Blockly.Lua.FUNCTION_NAME_PLACEHOLDER_ + '(item, count)',
        '  local t = {}',
@@ -41,37 +41,38 @@ Blockly.Lua['lists_repeat'] = function(block) {
        '  end',
        '  return t',
        'end']);
-  var element = Blockly.Lua.valueToCode(block, 'ITEM',
+  const element = Blockly.Lua.valueToCode(block, 'ITEM',
       Blockly.Lua.ORDER_NONE) || 'None';
-  var repeatCount = Blockly.Lua.valueToCode(block, 'NUM',
+  const repeatCount = Blockly.Lua.valueToCode(block, 'NUM',
       Blockly.Lua.ORDER_NONE) || '0';
-  var code = functionName + '(' + element + ', ' + repeatCount + ')';
+  const code = functionName + '(' + element + ', ' + repeatCount + ')';
   return [code, Blockly.Lua.ORDER_HIGH];
 };
 
 Blockly.Lua['lists_length'] = function(block) {
   // String or array length.
-  var list = Blockly.Lua.valueToCode(block, 'VALUE',
+  const list = Blockly.Lua.valueToCode(block, 'VALUE',
       Blockly.Lua.ORDER_UNARY) || '{}';
   return ['#' + list, Blockly.Lua.ORDER_UNARY];
 };
 
 Blockly.Lua['lists_isEmpty'] = function(block) {
   // Is the string null or array empty?
-  var list = Blockly.Lua.valueToCode(block, 'VALUE',
+  const list = Blockly.Lua.valueToCode(block, 'VALUE',
       Blockly.Lua.ORDER_UNARY) || '{}';
-  var code = '#' + list + ' == 0';
+  const code = '#' + list + ' == 0';
   return [code, Blockly.Lua.ORDER_RELATIONAL];
 };
 
 Blockly.Lua['lists_indexOf'] = function(block) {
   // Find an item in the list.
-  var item = Blockly.Lua.valueToCode(block, 'FIND',
+  const item = Blockly.Lua.valueToCode(block, 'FIND',
       Blockly.Lua.ORDER_NONE) || '\'\'';
-  var list = Blockly.Lua.valueToCode(block, 'VALUE',
+  const list = Blockly.Lua.valueToCode(block, 'VALUE',
       Blockly.Lua.ORDER_NONE) || '{}';
+  let functionName;
   if (block.getFieldValue('END') === 'FIRST') {
-    var functionName = Blockly.Lua.provideFunction_(
+    functionName = Blockly.Lua.provideFunction_(
         'first_index',
         ['function ' + Blockly.Lua.FUNCTION_NAME_PLACEHOLDER_ + '(t, elem)',
          '  for k, v in ipairs(t) do',
@@ -82,7 +83,7 @@ Blockly.Lua['lists_indexOf'] = function(block) {
          '  return 0',
          'end']);
   } else {
-    var functionName = Blockly.Lua.provideFunction_(
+    functionName = Blockly.Lua.provideFunction_(
         'last_index',
         ['function ' + Blockly.Lua.FUNCTION_NAME_PLACEHOLDER_ + '(t, elem)',
          '  for i = #t, 1, -1 do',
@@ -93,7 +94,7 @@ Blockly.Lua['lists_indexOf'] = function(block) {
          '  return 0',
          'end']);
   }
-  var code = functionName + '(' + list + ', ' + item + ')';
+  const code = functionName + '(' + list + ', ' + item + ')';
   return [code, Blockly.Lua.ORDER_HIGH];
 };
 
@@ -122,11 +123,11 @@ Blockly.Lua.lists.getIndex_ = function(listName, where, opt_at) {
 Blockly.Lua['lists_getIndex'] = function(block) {
   // Get element at index.
   // Note: Until January 2013 this block did not have MODE or WHERE inputs.
-  var mode = block.getFieldValue('MODE') || 'GET';
-  var where = block.getFieldValue('WHERE') || 'FROM_START';
-  var list = Blockly.Lua.valueToCode(block, 'VALUE', Blockly.Lua.ORDER_HIGH) ||
+  const mode = block.getFieldValue('MODE') || 'GET';
+  const where = block.getFieldValue('WHERE') || 'FROM_START';
+  const list = Blockly.Lua.valueToCode(block, 'VALUE', Blockly.Lua.ORDER_HIGH) ||
       '({})';
-  var getIndex_ = Blockly.Lua.lists.getIndex_;
+  const getIndex_ = Blockly.Lua.lists.getIndex_;
 
   // If `list` would be evaluated more than once (which is the case for LAST,
   // FROM_END, and RANDOM) and is non-trivial, make sure to access it only once.
@@ -135,21 +136,22 @@ Blockly.Lua['lists_getIndex'] = function(block) {
     // `list` is an expression, so we may not evaluate it more than once.
     if (mode === 'REMOVE') {
       // We can use multiple statements.
-      var atOrder = (where === 'FROM_END') ? Blockly.Lua.ORDER_ADDITIVE :
+      const atOrder = (where === 'FROM_END') ? Blockly.Lua.ORDER_ADDITIVE :
           Blockly.Lua.ORDER_NONE;
-      var at = Blockly.Lua.valueToCode(block, 'AT', atOrder) || '1';
-      var listVar = Blockly.Lua.nameDB_.getDistinctName(
+      let at = Blockly.Lua.valueToCode(block, 'AT', atOrder) || '1';
+      const listVar = Blockly.Lua.nameDB_.getDistinctName(
           'tmp_list', Blockly.VARIABLE_CATEGORY_NAME);
       at = getIndex_(listVar, where, at);
-      var code = listVar + ' = ' + list + '\n' +
+      const code = listVar + ' = ' + list + '\n' +
           'table.remove(' + listVar + ', ' + at + ')\n';
       return code;
     } else {
       // We need to create a procedure to avoid reevaluating values.
-      var at = Blockly.Lua.valueToCode(block, 'AT', Blockly.Lua.ORDER_NONE) ||
+      const at = Blockly.Lua.valueToCode(block, 'AT', Blockly.Lua.ORDER_NONE) ||
           '1';
+      let functionName;
       if (mode === 'GET') {
-        var functionName = Blockly.Lua.provideFunction_(
+        functionName = Blockly.Lua.provideFunction_(
             'list_get_' + where.toLowerCase(),
             ['function ' + Blockly.Lua.FUNCTION_NAME_PLACEHOLDER_ + '(t' +
                 // The value for 'FROM_END' and'FROM_START' depends on `at` so
@@ -159,7 +161,7 @@ Blockly.Lua['lists_getIndex'] = function(block) {
              '  return t[' + getIndex_('t', where, 'at') + ']',
              'end']);
       } else {  // `mode` === 'GET_REMOVE'
-        var functionName = Blockly.Lua.provideFunction_(
+        functionName = Blockly.Lua.provideFunction_(
             'list_remove_' + where.toLowerCase(),
             ['function ' + Blockly.Lua.FUNCTION_NAME_PLACEHOLDER_ + '(t' +
                 // The value for 'FROM_END' and'FROM_START' depends on `at` so
@@ -169,7 +171,7 @@ Blockly.Lua['lists_getIndex'] = function(block) {
              '  return table.remove(t, ' + getIndex_('t', where, 'at') + ')',
              'end']);
       }
-      var code = functionName + '(' + list +
+      const code = functionName + '(' + list +
           // The value for 'FROM_END' and 'FROM_START' depends on `at` so we
           // pass it.
           ((where === 'FROM_END' || where === 'FROM_START') ? ', ' + at : '') +
@@ -179,15 +181,15 @@ Blockly.Lua['lists_getIndex'] = function(block) {
   } else {
     // Either `list` is a simple variable, or we only need to refer to `list`
     // once.
-    var atOrder = (mode === 'GET' && where === 'FROM_END') ?
+    const atOrder = (mode === 'GET' && where === 'FROM_END') ?
         Blockly.Lua.ORDER_ADDITIVE : Blockly.Lua.ORDER_NONE;
-    var at = Blockly.Lua.valueToCode(block, 'AT', atOrder) || '1';
+    let at = Blockly.Lua.valueToCode(block, 'AT', atOrder) || '1';
     at = getIndex_(list, where, at);
     if (mode === 'GET') {
-      var code = list + '[' + at + ']';
+      const code = list + '[' + at + ']';
       return [code, Blockly.Lua.ORDER_HIGH];
     } else {
-      var code = 'table.remove(' + list + ', ' + at + ')';
+      const code = 'table.remove(' + list + ', ' + at + ')';
       if (mode === 'GET_REMOVE') {
         return [code, Blockly.Lua.ORDER_HIGH];
       } else {  // `mode` === 'REMOVE'
@@ -200,24 +202,24 @@ Blockly.Lua['lists_getIndex'] = function(block) {
 Blockly.Lua['lists_setIndex'] = function(block) {
   // Set element at index.
   // Note: Until February 2013 this block did not have MODE or WHERE inputs.
-  var list = Blockly.Lua.valueToCode(block, 'LIST',
+  let list = Blockly.Lua.valueToCode(block, 'LIST',
       Blockly.Lua.ORDER_HIGH) || '{}';
-  var mode = block.getFieldValue('MODE') || 'SET';
-  var where = block.getFieldValue('WHERE') || 'FROM_START';
-  var at = Blockly.Lua.valueToCode(block, 'AT',
+  const mode = block.getFieldValue('MODE') || 'SET';
+  const where = block.getFieldValue('WHERE') || 'FROM_START';
+  const at = Blockly.Lua.valueToCode(block, 'AT',
       Blockly.Lua.ORDER_ADDITIVE) || '1';
-  var value = Blockly.Lua.valueToCode(block, 'TO',
+  const value = Blockly.Lua.valueToCode(block, 'TO',
       Blockly.Lua.ORDER_NONE) || 'None';
-  var getIndex_ = Blockly.Lua.lists.getIndex_;
+  const getIndex_ = Blockly.Lua.lists.getIndex_;
 
-  var code = '';
+  let code = '';
   // If `list` would be evaluated more than once (which is the case for LAST,
   // FROM_END, and RANDOM) and is non-trivial, make sure to access it only once.
   if ((where === 'LAST' || where === 'FROM_END' || where === 'RANDOM') &&
       !list.match(/^\w+$/)) {
     // `list` is an expression, so we may not evaluate it more than once.
     // We can use multiple statements.
-    var listVar = Blockly.Lua.nameDB_.getDistinctName(
+    const listVar = Blockly.Lua.nameDB_.getDistinctName(
         'tmp_list', Blockly.VARIABLE_CATEGORY_NAME);
     code = listVar + ' = ' + list + '\n';
     list = listVar;
@@ -236,17 +238,17 @@ Blockly.Lua['lists_setIndex'] = function(block) {
 
 Blockly.Lua['lists_getSublist'] = function(block) {
   // Get sublist.
-  var list = Blockly.Lua.valueToCode(block, 'LIST',
+  const list = Blockly.Lua.valueToCode(block, 'LIST',
       Blockly.Lua.ORDER_NONE) || '{}';
-  var where1 = block.getFieldValue('WHERE1');
-  var where2 = block.getFieldValue('WHERE2');
-  var at1 = Blockly.Lua.valueToCode(block, 'AT1',
+  const where1 = block.getFieldValue('WHERE1');
+  const where2 = block.getFieldValue('WHERE2');
+  const at1 = Blockly.Lua.valueToCode(block, 'AT1',
       Blockly.Lua.ORDER_NONE) || '1';
-  var at2 = Blockly.Lua.valueToCode(block, 'AT2',
+  const at2 = Blockly.Lua.valueToCode(block, 'AT2',
       Blockly.Lua.ORDER_NONE) || '1';
-  var getIndex_ = Blockly.Lua.lists.getIndex_;
+  const getIndex_ = Blockly.Lua.lists.getIndex_;
 
-  var functionName = Blockly.Lua.provideFunction_(
+  const functionName = Blockly.Lua.provideFunction_(
       'list_sublist_' + where1.toLowerCase() + '_' + where2.toLowerCase(),
       ['function ' + Blockly.Lua.FUNCTION_NAME_PLACEHOLDER_ + '(source' +
           // The value for 'FROM_END' and'FROM_START' depends on `at` so
@@ -262,7 +264,7 @@ Blockly.Lua['lists_getSublist'] = function(block) {
        '  end',
        '  return t',
        'end']);
-  var code = functionName + '(' + list +
+  const code = functionName + '(' + list +
       // The value for 'FROM_END' and 'FROM_START' depends on `at` so we
       // pass it.
       ((where1 === 'FROM_END' || where1 === 'FROM_START') ? ', ' + at1 : '') +
@@ -273,12 +275,12 @@ Blockly.Lua['lists_getSublist'] = function(block) {
 
 Blockly.Lua['lists_sort'] = function(block) {
   // Block for sorting a list.
-  var list = Blockly.Lua.valueToCode(
+  const list = Blockly.Lua.valueToCode(
       block, 'LIST', Blockly.Lua.ORDER_NONE) || '{}';
-  var direction = block.getFieldValue('DIRECTION') === '1' ? 1 : -1;
-  var type = block.getFieldValue('TYPE');
+  const direction = block.getFieldValue('DIRECTION') === '1' ? 1 : -1;
+  const type = block.getFieldValue('TYPE');
 
-  var functionName = Blockly.Lua.provideFunction_(
+  const functionName = Blockly.Lua.provideFunction_(
       'list_sort',
       ['function ' + Blockly.Lua.FUNCTION_NAME_PLACEHOLDER_ +
           '(list, typev, direction)',
@@ -302,19 +304,19 @@ Blockly.Lua['lists_sort'] = function(block) {
        '  return t',
        'end']);
 
-  var code = functionName +
+  const code = functionName +
       '(' + list + ',"' + type + '", ' + direction + ')';
   return [code, Blockly.Lua.ORDER_HIGH];
 };
 
 Blockly.Lua['lists_split'] = function(block) {
   // Block for splitting text into a list, or joining a list into text.
-  var input = Blockly.Lua.valueToCode(block, 'INPUT',
+  let input = Blockly.Lua.valueToCode(block, 'INPUT',
       Blockly.Lua.ORDER_NONE);
-  var delimiter = Blockly.Lua.valueToCode(block, 'DELIM',
+  const delimiter = Blockly.Lua.valueToCode(block, 'DELIM',
       Blockly.Lua.ORDER_NONE) || '\'\'';
-  var mode = block.getFieldValue('MODE');
-  var functionName;
+  const mode = block.getFieldValue('MODE');
+  let functionName;
   if (mode === 'SPLIT') {
     if (!input) {
       input = '\'\'';
@@ -345,15 +347,15 @@ Blockly.Lua['lists_split'] = function(block) {
   } else {
     throw Error('Unknown mode: ' + mode);
   }
-  var code = functionName + '(' + input + ', ' + delimiter + ')';
+  const code = functionName + '(' + input + ', ' + delimiter + ')';
   return [code, Blockly.Lua.ORDER_HIGH];
 };
 
 Blockly.Lua['lists_reverse'] = function(block) {
   // Block for reversing a list.
-  var list = Blockly.Lua.valueToCode(block, 'LIST',
+  const list = Blockly.Lua.valueToCode(block, 'LIST',
       Blockly.Lua.ORDER_NONE) || '{}';
-  var functionName = Blockly.Lua.provideFunction_(
+  const functionName = Blockly.Lua.provideFunction_(
       'list_reverse',
       ['function ' + Blockly.Lua.FUNCTION_NAME_PLACEHOLDER_ + '(input)',
        '  local reversed = {}',
@@ -362,6 +364,6 @@ Blockly.Lua['lists_reverse'] = function(block) {
        '  end',
        '  return reversed',
        'end']);
-  var code = functionName + '(' + list + ')';
+  const code = functionName + '(' + list + ')';
   return [code, Blockly.Lua.ORDER_HIGH];
 };
diff --git a/generators/lua/logic.js b/generators/lua/logic.js
index 510866f37..df8c460f1 100644
--- a/generators/lua/logic.js
+++ b/generators/lua/logic.js
@@ -16,16 +16,16 @@ goog.require('Blockly.Lua');
 
 Blockly.Lua['controls_if'] = function(block) {
   // If/elseif/else condition.
-  var n = 0;
-  var code = '', branchCode, conditionCode;
+  let n = 0;
+  let code = '';
   if (Blockly.Lua.STATEMENT_PREFIX) {
     // Automatic prefix insertion is switched off for this block.  Add manually.
     code += Blockly.Lua.injectId(Blockly.Lua.STATEMENT_PREFIX, block);
   }
   do {
-    conditionCode = Blockly.Lua.valueToCode(block, 'IF' + n,
+    const conditionCode = Blockly.Lua.valueToCode(block, 'IF' + n,
         Blockly.Lua.ORDER_NONE) || 'false';
-    branchCode = Blockly.Lua.statementToCode(block, 'DO' + n);
+    let branchCode = Blockly.Lua.statementToCode(block, 'DO' + n);
     if (Blockly.Lua.STATEMENT_SUFFIX) {
       branchCode = Blockly.Lua.prefixLines(
           Blockly.Lua.injectId(Blockly.Lua.STATEMENT_SUFFIX, block),
@@ -37,7 +37,7 @@ Blockly.Lua['controls_if'] = function(block) {
   } while (block.getInput('IF' + n));
 
   if (block.getInput('ELSE') || Blockly.Lua.STATEMENT_SUFFIX) {
-    branchCode = Blockly.Lua.statementToCode(block, 'ELSE');
+    let branchCode = Blockly.Lua.statementToCode(block, 'ELSE');
     if (Blockly.Lua.STATEMENT_SUFFIX) {
       branchCode = Blockly.Lua.prefixLines(
           Blockly.Lua.injectId(Blockly.Lua.STATEMENT_SUFFIX, block),
@@ -52,7 +52,7 @@ Blockly.Lua['controls_ifelse'] = Blockly.Lua['controls_if'];
 
 Blockly.Lua['logic_compare'] = function(block) {
   // Comparison operator.
-  var OPERATORS = {
+  const OPERATORS = {
     'EQ': '==',
     'NEQ': '~=',
     'LT': '<',
@@ -60,29 +60,29 @@ Blockly.Lua['logic_compare'] = function(block) {
     'GT': '>',
     'GTE': '>='
   };
-  var operator = OPERATORS[block.getFieldValue('OP')];
-  var argument0 = Blockly.Lua.valueToCode(block, 'A',
+  const operator = OPERATORS[block.getFieldValue('OP')];
+  const argument0 = Blockly.Lua.valueToCode(block, 'A',
       Blockly.Lua.ORDER_RELATIONAL) || '0';
-  var argument1 = Blockly.Lua.valueToCode(block, 'B',
+  const argument1 = Blockly.Lua.valueToCode(block, 'B',
       Blockly.Lua.ORDER_RELATIONAL) || '0';
-  var code = argument0 + ' ' + operator + ' ' + argument1;
+  const code = argument0 + ' ' + operator + ' ' + argument1;
   return [code, Blockly.Lua.ORDER_RELATIONAL];
 };
 
 Blockly.Lua['logic_operation'] = function(block) {
   // Operations 'and', 'or'.
-  var operator = (block.getFieldValue('OP') === 'AND') ? 'and' : 'or';
-  var order = (operator === 'and') ? Blockly.Lua.ORDER_AND :
+  const operator = (block.getFieldValue('OP') === 'AND') ? 'and' : 'or';
+  const order = (operator === 'and') ? Blockly.Lua.ORDER_AND :
       Blockly.Lua.ORDER_OR;
-  var argument0 = Blockly.Lua.valueToCode(block, 'A', order);
-  var argument1 = Blockly.Lua.valueToCode(block, 'B', order);
+  let argument0 = Blockly.Lua.valueToCode(block, 'A', order);
+  let argument1 = Blockly.Lua.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 === 'and') ? 'true' : 'false';
+    const defaultArgument = (operator === 'and') ? 'true' : 'false';
     if (!argument0) {
       argument0 = defaultArgument;
     }
@@ -90,21 +90,21 @@ Blockly.Lua['logic_operation'] = function(block) {
       argument1 = defaultArgument;
     }
   }
-  var code = argument0 + ' ' + operator + ' ' + argument1;
+  const code = argument0 + ' ' + operator + ' ' + argument1;
   return [code, order];
 };
 
 Blockly.Lua['logic_negate'] = function(block) {
   // Negation.
-  var argument0 = Blockly.Lua.valueToCode(block, 'BOOL',
+  const argument0 = Blockly.Lua.valueToCode(block, 'BOOL',
       Blockly.Lua.ORDER_UNARY) || 'true';
-  var code = 'not ' + argument0;
+  const code = 'not ' + argument0;
   return [code, Blockly.Lua.ORDER_UNARY];
 };
 
 Blockly.Lua['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.Lua.ORDER_ATOMIC];
 };
 
@@ -115,12 +115,12 @@ Blockly.Lua['logic_null'] = function(block) {
 
 Blockly.Lua['logic_ternary'] = function(block) {
   // Ternary operator.
-  var value_if = Blockly.Lua.valueToCode(block, 'IF',
+  const value_if = Blockly.Lua.valueToCode(block, 'IF',
       Blockly.Lua.ORDER_AND) || 'false';
-  var value_then = Blockly.Lua.valueToCode(block, 'THEN',
+  const value_then = Blockly.Lua.valueToCode(block, 'THEN',
       Blockly.Lua.ORDER_AND) || 'nil';
-  var value_else = Blockly.Lua.valueToCode(block, 'ELSE',
+  const value_else = Blockly.Lua.valueToCode(block, 'ELSE',
       Blockly.Lua.ORDER_OR) || 'nil';
-  var code = value_if + ' and ' + value_then + ' or ' + value_else;
+  const code = value_if + ' and ' + value_then + ' or ' + value_else;
   return [code, Blockly.Lua.ORDER_OR];
 };
diff --git a/generators/lua/loops.js b/generators/lua/loops.js
index abc2996c3..2cc9696c7 100644
--- a/generators/lua/loops.js
+++ b/generators/lua/loops.js
@@ -43,12 +43,13 @@ Blockly.Lua.addContinueLabel_ = function(branch) {
 
 Blockly.Lua['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.Lua.valueToCode(block, 'TIMES',
+    repeats = Blockly.Lua.valueToCode(block, 'TIMES',
         Blockly.Lua.ORDER_NONE) || '0';
   }
   if (Blockly.isNumber(repeats)) {
@@ -56,12 +57,12 @@ Blockly.Lua['controls_repeat_ext'] = function(block) {
   } else {
     repeats = 'math.floor(' + repeats + ')';
   }
-  var branch = Blockly.Lua.statementToCode(block, 'DO');
+  let branch = Blockly.Lua.statementToCode(block, 'DO');
   branch = Blockly.Lua.addLoopTrap(branch, block);
   branch = Blockly.Lua.addContinueLabel_(branch);
-  var loopVar = Blockly.Lua.nameDB_.getDistinctName(
+  const loopVar = Blockly.Lua.nameDB_.getDistinctName(
       'count', Blockly.VARIABLE_CATEGORY_NAME);
-  var code = 'for ' + loopVar + ' = 1, ' + repeats + ' do\n' +
+  const code = 'for ' + loopVar + ' = 1, ' + repeats + ' do\n' +
       branch + 'end\n';
   return code;
 };
@@ -70,11 +71,11 @@ Blockly.Lua['controls_repeat'] = Blockly.Lua['controls_repeat_ext'];
 
 Blockly.Lua['controls_whileUntil'] = function(block) {
   // Do while/until loop.
-  var until = block.getFieldValue('MODE') === 'UNTIL';
-  var argument0 = Blockly.Lua.valueToCode(block, 'BOOL',
+  const until = block.getFieldValue('MODE') === 'UNTIL';
+  let argument0 = Blockly.Lua.valueToCode(block, 'BOOL',
       until ? Blockly.Lua.ORDER_UNARY :
       Blockly.Lua.ORDER_NONE) || 'false';
-  var branch = Blockly.Lua.statementToCode(block, 'DO');
+  let branch = Blockly.Lua.statementToCode(block, 'DO');
   branch = Blockly.Lua.addLoopTrap(branch, block);
   branch = Blockly.Lua.addContinueLabel_(branch);
   if (until) {
@@ -85,24 +86,24 @@ Blockly.Lua['controls_whileUntil'] = function(block) {
 
 Blockly.Lua['controls_for'] = function(block) {
   // For loop.
-  var variable0 = Blockly.Lua.nameDB_.getName(
+  const variable0 = Blockly.Lua.nameDB_.getName(
       block.getFieldValue('VAR'), Blockly.VARIABLE_CATEGORY_NAME);
-  var startVar = Blockly.Lua.valueToCode(block, 'FROM',
+  const startVar = Blockly.Lua.valueToCode(block, 'FROM',
       Blockly.Lua.ORDER_NONE) || '0';
-  var endVar = Blockly.Lua.valueToCode(block, 'TO',
+  const endVar = Blockly.Lua.valueToCode(block, 'TO',
       Blockly.Lua.ORDER_NONE) || '0';
-  var increment = Blockly.Lua.valueToCode(block, 'BY',
+  const increment = Blockly.Lua.valueToCode(block, 'BY',
       Blockly.Lua.ORDER_NONE) || '1';
-  var branch = Blockly.Lua.statementToCode(block, 'DO');
+  let branch = Blockly.Lua.statementToCode(block, 'DO');
   branch = Blockly.Lua.addLoopTrap(branch, block);
   branch = Blockly.Lua.addContinueLabel_(branch);
-  var code = '';
-  var incValue;
+  let code = '';
+  let incValue;
   if (Blockly.isNumber(startVar) && Blockly.isNumber(endVar) &&
       Blockly.isNumber(increment)) {
     // All arguments are simple numbers.
-    var up = Number(startVar) <= Number(endVar);
-    var step = Math.abs(Number(increment));
+    const up = Number(startVar) <= Number(endVar);
+    const step = Math.abs(Number(increment));
     incValue = (up ? '' : '-') + step;
   } else {
     code = '';
@@ -128,21 +129,21 @@ Blockly.Lua['controls_for'] = function(block) {
 
 Blockly.Lua['controls_forEach'] = function(block) {
   // For each loop.
-  var variable0 = Blockly.Lua.nameDB_.getName(
+  const variable0 = Blockly.Lua.nameDB_.getName(
       block.getFieldValue('VAR'), Blockly.VARIABLE_CATEGORY_NAME);
-  var argument0 = Blockly.Lua.valueToCode(block, 'LIST',
+  const argument0 = Blockly.Lua.valueToCode(block, 'LIST',
       Blockly.Lua.ORDER_NONE) || '{}';
-  var branch = Blockly.Lua.statementToCode(block, 'DO');
+  let branch = Blockly.Lua.statementToCode(block, 'DO');
   branch = Blockly.Lua.addLoopTrap(branch, block);
   branch = Blockly.Lua.addContinueLabel_(branch);
-  var code = 'for _, ' + variable0 + ' in ipairs(' + argument0 + ') do \n' +
+  const code = 'for _, ' + variable0 + ' in ipairs(' + argument0 + ') do \n' +
       branch + 'end\n';
   return code;
 };
 
 Blockly.Lua['controls_flow_statements'] = function(block) {
   // Flow statements: continue, break.
-  var xfix = '';
+  let xfix = '';
   if (Blockly.Lua.STATEMENT_PREFIX) {
     // Automatic prefix insertion is switched off for this block.  Add manually.
     xfix += Blockly.Lua.injectId(Blockly.Lua.STATEMENT_PREFIX, block);
@@ -153,7 +154,7 @@ Blockly.Lua['controls_flow_statements'] = function(block) {
     xfix += Blockly.Lua.injectId(Blockly.Lua.STATEMENT_SUFFIX, block);
   }
   if (Blockly.Lua.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/lua/math.js b/generators/lua/math.js
index 9d450ff4f..aab654b86 100644
--- a/generators/lua/math.js
+++ b/generators/lua/math.js
@@ -16,35 +16,34 @@ goog.require('Blockly.Lua');
 
 Blockly.Lua['math_number'] = function(block) {
   // Numeric value.
-  var code = Number(block.getFieldValue('NUM'));
-  var order = code < 0 ? Blockly.Lua.ORDER_UNARY :
+  const code = Number(block.getFieldValue('NUM'));
+  const order = code < 0 ? Blockly.Lua.ORDER_UNARY :
               Blockly.Lua.ORDER_ATOMIC;
   return [code, order];
 };
 
 Blockly.Lua['math_arithmetic'] = function(block) {
   // Basic arithmetic operators, and power.
-  var OPERATORS = {
+  const OPERATORS = {
     ADD: [' + ', Blockly.Lua.ORDER_ADDITIVE],
     MINUS: [' - ', Blockly.Lua.ORDER_ADDITIVE],
     MULTIPLY: [' * ', Blockly.Lua.ORDER_MULTIPLICATIVE],
     DIVIDE: [' / ', Blockly.Lua.ORDER_MULTIPLICATIVE],
     POWER: [' ^ ', Blockly.Lua.ORDER_EXPONENTIATION]
   };
-  var tuple = OPERATORS[block.getFieldValue('OP')];
-  var operator = tuple[0];
-  var order = tuple[1];
-  var argument0 = Blockly.Lua.valueToCode(block, 'A', order) || '0';
-  var argument1 = Blockly.Lua.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.Lua.valueToCode(block, 'A', order) || '0';
+  const argument1 = Blockly.Lua.valueToCode(block, 'B', order) || '0';
+  const code = argument0 + operator + argument1;
   return [code, order];
 };
 
 Blockly.Lua['math_single'] = function(block) {
   // Math operators with single operand.
-  var operator = block.getFieldValue('OP');
-  var code;
-  var arg;
+  const operator = block.getFieldValue('OP');
+  let arg;
   if (operator === 'NEG') {
     // Negation is a special case given its different operator precedence.
     arg = Blockly.Lua.valueToCode(block, 'NUM',
@@ -63,6 +62,8 @@ Blockly.Lua['math_single'] = function(block) {
     arg = Blockly.Lua.valueToCode(block, 'NUM',
         Blockly.Lua.ORDER_NONE) || '0';
   }
+
+  let code;
   switch (operator) {
     case 'ABS':
       code = 'math.abs(' + arg + ')';
@@ -115,7 +116,7 @@ Blockly.Lua['math_single'] = function(block) {
 
 Blockly.Lua['math_constant'] = function(block) {
   // Constants: PI, E, the Golden Ratio, sqrt(2), 1/sqrt(2), INFINITY.
-  var CONSTANTS = {
+  const CONSTANTS = {
     PI: ['math.pi', Blockly.Lua.ORDER_HIGH],
     E: ['math.exp(1)', Blockly.Lua.ORDER_HIGH],
     GOLDEN_RATIO: ['(1 + math.sqrt(5)) / 2', Blockly.Lua.ORDER_MULTIPLICATIVE],
@@ -129,13 +130,13 @@ Blockly.Lua['math_constant'] = function(block) {
 Blockly.Lua['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.Lua.valueToCode(block, 'NUMBER_TO_CHECK',
+  const number_to_check = Blockly.Lua.valueToCode(block, 'NUMBER_TO_CHECK',
       Blockly.Lua.ORDER_MULTIPLICATIVE) || '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.Lua.provideFunction_(
+    const functionName = Blockly.Lua.provideFunction_(
         'math_isPrime',
         ['function ' + Blockly.Lua.FUNCTION_NAME_PLACEHOLDER_ + '(n)',
          '  -- https://en.wikipedia.org/wiki/Primality_test#Naive_methods',
@@ -174,8 +175,8 @@ Blockly.Lua['math_number_property'] = function(block) {
     case 'NEGATIVE':
       code = number_to_check + ' < 0';
       break;
-    case 'DIVISIBLE_BY':
-      var divisor = Blockly.Lua.valueToCode(block, 'DIVISOR',
+    case 'DIVISIBLE_BY': {
+      const divisor = Blockly.Lua.valueToCode(block, 'DIVISOR',
           Blockly.Lua.ORDER_MULTIPLICATIVE);
       // If 'divisor' is some code that evals to 0, Lua will produce a nan.
       // Let's produce nil if we can determine this at compile-time.
@@ -187,15 +188,16 @@ Blockly.Lua['math_number_property'] = function(block) {
       // because nil is false, so allow a runtime failure. :-(
       code = number_to_check + ' % ' + divisor + ' == 0';
       break;
+    }
   }
   return [code, Blockly.Lua.ORDER_RELATIONAL];
 };
 
 Blockly.Lua['math_change'] = function(block) {
   // Add to a variable in place.
-  var argument0 = Blockly.Lua.valueToCode(block, 'DELTA',
+  const argument0 = Blockly.Lua.valueToCode(block, 'DELTA',
       Blockly.Lua.ORDER_ADDITIVE) || '0';
-  var varName = Blockly.Lua.nameDB_.getName(
+  const varName = Blockly.Lua.nameDB_.getName(
       block.getFieldValue('VAR'), Blockly.VARIABLE_CATEGORY_NAME);
   return varName + ' = ' + varName + ' + ' + argument0 + '\n';
 };
@@ -207,10 +209,10 @@ Blockly.Lua['math_trig'] = Blockly.Lua['math_single'];
 
 Blockly.Lua['math_on_list'] = function(block) {
   // Math functions for lists.
-  var func = block.getFieldValue('OP');
-  var list = Blockly.Lua.valueToCode(block, 'LIST',
+  const func = block.getFieldValue('OP');
+  const list = Blockly.Lua.valueToCode(block, 'LIST',
       Blockly.Lua.ORDER_NONE) || '{}';
-  var functionName;
+  let functionName;
 
   // Functions needed in more than one case.
   function provideSum() {
@@ -375,34 +377,34 @@ Blockly.Lua['math_on_list'] = function(block) {
 
 Blockly.Lua['math_modulo'] = function(block) {
   // Remainder computation.
-  var argument0 = Blockly.Lua.valueToCode(block, 'DIVIDEND',
+  const argument0 = Blockly.Lua.valueToCode(block, 'DIVIDEND',
       Blockly.Lua.ORDER_MULTIPLICATIVE) || '0';
-  var argument1 = Blockly.Lua.valueToCode(block, 'DIVISOR',
+  const argument1 = Blockly.Lua.valueToCode(block, 'DIVISOR',
       Blockly.Lua.ORDER_MULTIPLICATIVE) || '0';
-  var code = argument0 + ' % ' + argument1;
+  const code = argument0 + ' % ' + argument1;
   return [code, Blockly.Lua.ORDER_MULTIPLICATIVE];
 };
 
 Blockly.Lua['math_constrain'] = function(block) {
   // Constrain a number between two limits.
-  var argument0 = Blockly.Lua.valueToCode(block, 'VALUE',
+  const argument0 = Blockly.Lua.valueToCode(block, 'VALUE',
       Blockly.Lua.ORDER_NONE) || '0';
-  var argument1 = Blockly.Lua.valueToCode(block, 'LOW',
+  const argument1 = Blockly.Lua.valueToCode(block, 'LOW',
       Blockly.Lua.ORDER_NONE) || '-math.huge';
-  var argument2 = Blockly.Lua.valueToCode(block, 'HIGH',
+  const argument2 = Blockly.Lua.valueToCode(block, 'HIGH',
       Blockly.Lua.ORDER_NONE) || 'math.huge';
-  var code = 'math.min(math.max(' + argument0 + ', ' + argument1 + '), ' +
+  const code = 'math.min(math.max(' + argument0 + ', ' + argument1 + '), ' +
       argument2 + ')';
   return [code, Blockly.Lua.ORDER_HIGH];
 };
 
 Blockly.Lua['math_random_int'] = function(block) {
   // Random integer between [X] and [Y].
-  var argument0 = Blockly.Lua.valueToCode(block, 'FROM',
+  const argument0 = Blockly.Lua.valueToCode(block, 'FROM',
       Blockly.Lua.ORDER_NONE) || '0';
-  var argument1 = Blockly.Lua.valueToCode(block, 'TO',
+  const argument1 = Blockly.Lua.valueToCode(block, 'TO',
       Blockly.Lua.ORDER_NONE) || '0';
-  var code = 'math.random(' + argument0 + ', ' + argument1 + ')';
+  const code = 'math.random(' + argument0 + ', ' + argument1 + ')';
   return [code, Blockly.Lua.ORDER_HIGH];
 };
 
@@ -413,9 +415,9 @@ Blockly.Lua['math_random_float'] = function(block) {
 
 Blockly.Lua['math_atan2'] = function(block) {
   // Arctangent of point (X, Y) in degrees from -180 to 180.
-  var argument0 = Blockly.Lua.valueToCode(block, 'X',
+  const argument0 = Blockly.Lua.valueToCode(block, 'X',
       Blockly.Lua.ORDER_NONE) || '0';
-  var argument1 = Blockly.Lua.valueToCode(block, 'Y',
+  const argument1 = Blockly.Lua.valueToCode(block, 'Y',
       Blockly.Lua.ORDER_NONE) || '0';
   return ['math.deg(math.atan2(' + argument1 + ', ' + argument0 + '))',
       Blockly.Lua.ORDER_HIGH];
diff --git a/generators/lua/procedures.js b/generators/lua/procedures.js
index c89ea72b7..70dfdd631 100644
--- a/generators/lua/procedures.js
+++ b/generators/lua/procedures.js
@@ -16,9 +16,9 @@ goog.require('Blockly.Lua');
 
 Blockly.Lua['procedures_defreturn'] = function(block) {
   // Define a procedure with a return value.
-  var funcName = Blockly.Lua.nameDB_.getName(
+  const funcName = Blockly.Lua.nameDB_.getName(
       block.getFieldValue('NAME'), Blockly.PROCEDURE_CATEGORY_NAME);
-  var xfix1 = '';
+  let xfix1 = '';
   if (Blockly.Lua.STATEMENT_PREFIX) {
     xfix1 += Blockly.Lua.injectId(Blockly.Lua.STATEMENT_PREFIX, block);
   }
@@ -28,16 +28,16 @@ Blockly.Lua['procedures_defreturn'] = function(block) {
   if (xfix1) {
     xfix1 = Blockly.Lua.prefixLines(xfix1, Blockly.Lua.INDENT);
   }
-  var loopTrap = '';
+  let loopTrap = '';
   if (Blockly.Lua.INFINITE_LOOP_TRAP) {
     loopTrap = Blockly.Lua.prefixLines(
         Blockly.Lua.injectId(Blockly.Lua.INFINITE_LOOP_TRAP, block),
         Blockly.Lua.INDENT);
   }
-  var branch = Blockly.Lua.statementToCode(block, 'STACK');
-  var returnValue = Blockly.Lua.valueToCode(block, 'RETURN',
+  let branch = Blockly.Lua.statementToCode(block, 'STACK');
+  let returnValue = Blockly.Lua.valueToCode(block, 'RETURN',
       Blockly.Lua.ORDER_NONE) || '';
-  var xfix2 = '';
+  let xfix2 = '';
   if (branch && returnValue) {
     // After executing the function body, revisit this block for the return.
     xfix2 = xfix1;
@@ -47,13 +47,13 @@ Blockly.Lua['procedures_defreturn'] = function(block) {
   } else if (!branch) {
     branch = '';
   }
-  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.Lua.nameDB_.getName(variables[i],
         Blockly.VARIABLE_CATEGORY_NAME);
   }
-  var code = 'function ' + funcName + '(' + args.join(', ') + ')\n' +
+  let code = 'function ' + funcName + '(' + args.join(', ') + ')\n' +
       xfix1 + loopTrap + branch + xfix2 + returnValue + 'end\n';
   code = Blockly.Lua.scrub_(block, code);
   // Add % so as not to collide with helper functions in definitions list.
@@ -68,15 +68,15 @@ Blockly.Lua['procedures_defnoreturn'] =
 
 Blockly.Lua['procedures_callreturn'] = function(block) {
   // Call a procedure with a return value.
-  var funcName = Blockly.Lua.nameDB_.getName(
+  const funcName = Blockly.Lua.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.Lua.valueToCode(block, 'ARG' + i,
         Blockly.Lua.ORDER_NONE) || 'nil';
   }
-  var code = funcName + '(' + args.join(', ') + ')';
+  const code = funcName + '(' + args.join(', ') + ')';
   return [code, Blockly.Lua.ORDER_HIGH];
 };
 
@@ -84,15 +84,15 @@ Blockly.Lua['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.Lua['procedures_callreturn'](block);
+  const tuple = Blockly.Lua['procedures_callreturn'](block);
   return tuple[0] + '\n';
 };
 
 Blockly.Lua['procedures_ifreturn'] = function(block) {
   // Conditionally return value from a procedure.
-  var condition = Blockly.Lua.valueToCode(block, 'CONDITION',
+  const condition = Blockly.Lua.valueToCode(block, 'CONDITION',
       Blockly.Lua.ORDER_NONE) || 'false';
-  var code = 'if ' + condition + ' then\n';
+  let code = 'if ' + condition + ' then\n';
   if (Blockly.Lua.STATEMENT_SUFFIX) {
     // Inject any statement suffix here since the regular one at the end
     // will not get executed if the return is triggered.
@@ -101,7 +101,7 @@ Blockly.Lua['procedures_ifreturn'] = function(block) {
         Blockly.Lua.INDENT);
   }
   if (block.hasReturnValue_) {
-    var value = Blockly.Lua.valueToCode(block, 'VALUE',
+    const value = Blockly.Lua.valueToCode(block, 'VALUE',
         Blockly.Lua.ORDER_NONE) || 'nil';
     code += Blockly.Lua.INDENT + 'return ' + value + '\n';
   } else {
diff --git a/generators/lua/text.js b/generators/lua/text.js
index ce47ffc7f..035df30fc 100644
--- a/generators/lua/text.js
+++ b/generators/lua/text.js
@@ -16,14 +16,14 @@ goog.require('Blockly.Lua');
 
 Blockly.Lua['text'] = function(block) {
   // Text value.
-  var code = Blockly.Lua.quote_(block.getFieldValue('TEXT'));
+  const code = Blockly.Lua.quote_(block.getFieldValue('TEXT'));
   return [code, Blockly.Lua.ORDER_ATOMIC];
 };
 
 Blockly.Lua['text_multiline'] = function(block) {
   // Text value.
-  var code = Blockly.Lua.multiline_quote_(block.getFieldValue('TEXT'));
-  var order = code.indexOf('..') !== -1 ? Blockly.Lua.ORDER_CONCATENATION :
+  const code = Blockly.Lua.multiline_quote_(block.getFieldValue('TEXT'));
+  const order = code.indexOf('..') !== -1 ? Blockly.Lua.ORDER_CONCATENATION :
       Blockly.Lua.ORDER_ATOMIC;
   return [code, order];
 };
@@ -33,59 +33,60 @@ Blockly.Lua['text_join'] = function(block) {
   if (block.itemCount_ === 0) {
     return ['\'\'', Blockly.Lua.ORDER_ATOMIC];
   } else if (block.itemCount_ === 1) {
-    var element = Blockly.Lua.valueToCode(block, 'ADD0',
+    const element = Blockly.Lua.valueToCode(block, 'ADD0',
         Blockly.Lua.ORDER_NONE) || '\'\'';
-    var code = 'tostring(' + element + ')';
+    const code = 'tostring(' + element + ')';
     return [code, Blockly.Lua.ORDER_HIGH];
   } else if (block.itemCount_ === 2) {
-    var element0 = Blockly.Lua.valueToCode(block, 'ADD0',
+    const element0 = Blockly.Lua.valueToCode(block, 'ADD0',
         Blockly.Lua.ORDER_CONCATENATION) || '\'\'';
-    var element1 = Blockly.Lua.valueToCode(block, 'ADD1',
+    const element1 = Blockly.Lua.valueToCode(block, 'ADD1',
         Blockly.Lua.ORDER_CONCATENATION) || '\'\'';
-    var code = element0 + ' .. ' + element1;
+    const code = element0 + ' .. ' + element1;
     return [code, Blockly.Lua.ORDER_CONCATENATION];
   } else {
-    var elements = [];
-    for (var i = 0; i < block.itemCount_; i++) {
+    const elements = [];
+    for (let i = 0; i < block.itemCount_; i++) {
       elements[i] = Blockly.Lua.valueToCode(block, 'ADD' + i,
           Blockly.Lua.ORDER_NONE) || '\'\'';
     }
-    var code = 'table.concat({' + elements.join(', ') + '})';
+    const code = 'table.concat({' + elements.join(', ') + '})';
     return [code, Blockly.Lua.ORDER_HIGH];
   }
 };
 
 Blockly.Lua['text_append'] = function(block) {
   // Append to a variable in place.
-  var varName = Blockly.Lua.nameDB_.getName(
+  const varName = Blockly.Lua.nameDB_.getName(
       block.getFieldValue('VAR'), Blockly.VARIABLE_CATEGORY_NAME);
-  var value = Blockly.Lua.valueToCode(block, 'TEXT',
+  const value = Blockly.Lua.valueToCode(block, 'TEXT',
       Blockly.Lua.ORDER_CONCATENATION) || '\'\'';
   return varName + ' = ' + varName + ' .. ' + value + '\n';
 };
 
 Blockly.Lua['text_length'] = function(block) {
   // String or array length.
-  var text = Blockly.Lua.valueToCode(block, 'VALUE',
+  const text = Blockly.Lua.valueToCode(block, 'VALUE',
       Blockly.Lua.ORDER_UNARY) || '\'\'';
   return ['#' + text, Blockly.Lua.ORDER_UNARY];
 };
 
 Blockly.Lua['text_isEmpty'] = function(block) {
   // Is the string null or array empty?
-  var text = Blockly.Lua.valueToCode(block, 'VALUE',
+  const text = Blockly.Lua.valueToCode(block, 'VALUE',
       Blockly.Lua.ORDER_UNARY) || '\'\'';
   return ['#' + text + ' == 0', Blockly.Lua.ORDER_RELATIONAL];
 };
 
 Blockly.Lua['text_indexOf'] = function(block) {
   // Search the text for a substring.
-  var substring = Blockly.Lua.valueToCode(block, 'FIND',
+  const substring = Blockly.Lua.valueToCode(block, 'FIND',
       Blockly.Lua.ORDER_NONE) || '\'\'';
-  var text = Blockly.Lua.valueToCode(block, 'VALUE',
+  const text = Blockly.Lua.valueToCode(block, 'VALUE',
       Blockly.Lua.ORDER_NONE) || '\'\'';
+  let functionName;
   if (block.getFieldValue('END') === 'FIRST') {
-    var functionName = Blockly.Lua.provideFunction_(
+    functionName = Blockly.Lua.provideFunction_(
         'firstIndexOf',
         ['function ' + Blockly.Lua.FUNCTION_NAME_PLACEHOLDER_ +
              '(str, substr) ',
@@ -97,7 +98,7 @@ Blockly.Lua['text_indexOf'] = function(block) {
          '  end',
          'end']);
   } else {
-    var functionName = Blockly.Lua.provideFunction_(
+    functionName = Blockly.Lua.provideFunction_(
         'lastIndexOf',
         ['function ' + Blockly.Lua.FUNCTION_NAME_PLACEHOLDER_ +
              '(str, substr)',
@@ -109,22 +110,22 @@ Blockly.Lua['text_indexOf'] = function(block) {
          '  return 0',
          'end']);
   }
-  var code = functionName + '(' + text + ', ' + substring + ')';
+  const code = functionName + '(' + text + ', ' + substring + ')';
   return [code, Blockly.Lua.ORDER_HIGH];
 };
 
 Blockly.Lua['text_charAt'] = function(block) {
   // Get letter at index.
   // Note: Until January 2013 this block did not have the WHERE input.
-  var where = block.getFieldValue('WHERE') || 'FROM_START';
-  var atOrder = (where === 'FROM_END') ? Blockly.Lua.ORDER_UNARY :
+  const where = block.getFieldValue('WHERE') || 'FROM_START';
+  const atOrder = (where === 'FROM_END') ? Blockly.Lua.ORDER_UNARY :
       Blockly.Lua.ORDER_NONE;
-  var at = Blockly.Lua.valueToCode(block, 'AT', atOrder) || '1';
-  var text = Blockly.Lua.valueToCode(block, 'VALUE',
+  const at = Blockly.Lua.valueToCode(block, 'AT', atOrder) || '1';
+  const text = Blockly.Lua.valueToCode(block, 'VALUE',
       Blockly.Lua.ORDER_NONE) || '\'\'';
-  var code;
+  let code;
   if (where === 'RANDOM') {
-    var functionName = Blockly.Lua.provideFunction_(
+    const functionName = Blockly.Lua.provideFunction_(
         'text_random_letter',
         ['function ' + Blockly.Lua.FUNCTION_NAME_PLACEHOLDER_ + '(str)',
          '  local index = math.random(string.len(str))',
@@ -132,15 +133,16 @@ Blockly.Lua['text_charAt'] = function(block) {
          'end']);
     code = functionName + '(' + text + ')';
   } else {
+    let start;
     if (where === 'FIRST') {
-      var start = '1';
+      start = '1';
     } else if (where === 'LAST') {
-      var start = '-1';
+      start = '-1';
     } else {
       if (where === 'FROM_START') {
-        var start = at;
+        start = at;
       } else if (where === 'FROM_END') {
-        var start = '-' + at;
+        start = '-' + at;
       } else {
         throw Error('Unhandled option (text_charAt).');
       }
@@ -149,7 +151,7 @@ Blockly.Lua['text_charAt'] = function(block) {
       code = 'string.sub(' + text + ', ' + start + ', ' + start + ')';
     } else {
       // use function to avoid reevaluation
-      var functionName = Blockly.Lua.provideFunction_(
+      const functionName = Blockly.Lua.provideFunction_(
           'text_char_at',
           ['function ' + Blockly.Lua.FUNCTION_NAME_PLACEHOLDER_ +
                '(str, index)',
@@ -163,53 +165,56 @@ Blockly.Lua['text_charAt'] = function(block) {
 
 Blockly.Lua['text_getSubstring'] = function(block) {
   // Get substring.
-  var text = Blockly.Lua.valueToCode(block, 'STRING',
+  const text = Blockly.Lua.valueToCode(block, 'STRING',
       Blockly.Lua.ORDER_NONE) || '\'\'';
 
   // Get start index.
-  var where1 = block.getFieldValue('WHERE1');
-  var at1Order = (where1 === 'FROM_END') ? Blockly.Lua.ORDER_UNARY :
+  const where1 = block.getFieldValue('WHERE1');
+  const at1Order = (where1 === 'FROM_END') ? Blockly.Lua.ORDER_UNARY :
       Blockly.Lua.ORDER_NONE;
-  var at1 = Blockly.Lua.valueToCode(block, 'AT1', at1Order) || '1';
+  const at1 = Blockly.Lua.valueToCode(block, 'AT1', at1Order) || '1';
+  let start;
   if (where1 === 'FIRST') {
-    var start = 1;
+    start = 1;
   } else if (where1 === 'FROM_START') {
-    var start = at1;
+    start = at1;
   } else if (where1 === 'FROM_END') {
-    var start = '-' + at1;
+    start = '-' + at1;
   } else {
     throw Error('Unhandled option (text_getSubstring)');
   }
 
   // Get end index.
-  var where2 = block.getFieldValue('WHERE2');
-  var at2Order = (where2 === 'FROM_END') ? Blockly.Lua.ORDER_UNARY :
+  const where2 = block.getFieldValue('WHERE2');
+  const at2Order = (where2 === 'FROM_END') ? Blockly.Lua.ORDER_UNARY :
       Blockly.Lua.ORDER_NONE;
-  var at2 = Blockly.Lua.valueToCode(block, 'AT2', at2Order) || '1';
+  const at2 = Blockly.Lua.valueToCode(block, 'AT2', at2Order) || '1';
+  let end;
   if (where2 === 'LAST') {
-    var end = -1;
+    end = -1;
   } else if (where2 === 'FROM_START') {
-    var end = at2;
+    end = at2;
   } else if (where2 === 'FROM_END') {
-    var end = '-' + at2;
+    end = '-' + at2;
   } else {
     throw Error('Unhandled option (text_getSubstring)');
   }
-  var code = 'string.sub(' + text + ', ' + start + ', ' + end + ')';
+  const code = 'string.sub(' + text + ', ' + start + ', ' + end + ')';
   return [code, Blockly.Lua.ORDER_HIGH];
 };
 
 Blockly.Lua['text_changeCase'] = function(block) {
   // Change capitalization.
-  var operator = block.getFieldValue('CASE');
-  var text = Blockly.Lua.valueToCode(block, 'TEXT',
+  const operator = block.getFieldValue('CASE');
+  const text = Blockly.Lua.valueToCode(block, 'TEXT',
       Blockly.Lua.ORDER_NONE) || '\'\'';
+  let functionName;
   if (operator === 'UPPERCASE') {
-    var functionName = 'string.upper';
+    functionName = 'string.upper';
   } else if (operator === 'LOWERCASE') {
-    var functionName = 'string.lower';
+    functionName = 'string.lower';
   } else if (operator === 'TITLECASE') {
-    var functionName = Blockly.Lua.provideFunction_(
+    functionName = Blockly.Lua.provideFunction_(
         'text_titlecase',
         // There are shorter versions at
         // http://lua-users.org/wiki/SciteTitleCase
@@ -232,52 +237,53 @@ Blockly.Lua['text_changeCase'] = function(block) {
          '  return table.concat(buf)',
          'end']);
   }
-  var code = functionName + '(' + text + ')';
+  const code = functionName + '(' + text + ')';
   return [code, Blockly.Lua.ORDER_HIGH];
 };
 
 Blockly.Lua['text_trim'] = function(block) {
   // Trim spaces.
-  var OPERATORS = {
+  const OPERATORS = {
     LEFT: '^%s*(,-)',
     RIGHT: '(.-)%s*$',
     BOTH: '^%s*(.-)%s*$'
   };
-  var operator = OPERATORS[block.getFieldValue('MODE')];
-  var text = Blockly.Lua.valueToCode(block, 'TEXT',
+  const operator = OPERATORS[block.getFieldValue('MODE')];
+  const text = Blockly.Lua.valueToCode(block, 'TEXT',
       Blockly.Lua.ORDER_NONE) || '\'\'';
-  var code = 'string.gsub(' + text + ', "' + operator + '", "%1")';
+  const code = 'string.gsub(' + text + ', "' + operator + '", "%1")';
   return [code, Blockly.Lua.ORDER_HIGH];
 };
 
 Blockly.Lua['text_print'] = function(block) {
   // Print statement.
-  var msg = Blockly.Lua.valueToCode(block, 'TEXT',
+  const msg = Blockly.Lua.valueToCode(block, 'TEXT',
       Blockly.Lua.ORDER_NONE) || '\'\'';
   return 'print(' + msg + ')\n';
 };
 
 Blockly.Lua['text_prompt_ext'] = function(block) {
   // Prompt function.
+  let msg;
   if (block.getField('TEXT')) {
     // Internal message.
-    var msg = Blockly.Lua.quote_(block.getFieldValue('TEXT'));
+    msg = Blockly.Lua.quote_(block.getFieldValue('TEXT'));
   } else {
     // External message.
-    var msg = Blockly.Lua.valueToCode(block, 'TEXT',
+    msg = Blockly.Lua.valueToCode(block, 'TEXT',
         Blockly.Lua.ORDER_NONE) || '\'\'';
   }
 
-  var functionName = Blockly.Lua.provideFunction_(
+  const functionName = Blockly.Lua.provideFunction_(
       'text_prompt',
       ['function ' + Blockly.Lua.FUNCTION_NAME_PLACEHOLDER_ + '(msg)',
        '  io.write(msg)',
        '  io.flush()',
        '  return io.read()',
        'end']);
-  var code = functionName + '(' + msg + ')';
+  let code = functionName + '(' + msg + ')';
 
-  var toNumber = block.getFieldValue('TYPE') === 'NUMBER';
+  const toNumber = block.getFieldValue('TYPE') === 'NUMBER';
   if (toNumber) {
     code = 'tonumber(' + code + ', 10)';
   }
@@ -287,11 +293,11 @@ Blockly.Lua['text_prompt_ext'] = function(block) {
 Blockly.Lua['text_prompt'] = Blockly.Lua['text_prompt_ext'];
 
 Blockly.Lua['text_count'] = function(block) {
-  var text = Blockly.Lua.valueToCode(block, 'TEXT',
+  const text = Blockly.Lua.valueToCode(block, 'TEXT',
       Blockly.Lua.ORDER_NONE) || '\'\'';
-  var sub = Blockly.Lua.valueToCode(block, 'SUB',
+  const sub = Blockly.Lua.valueToCode(block, 'SUB',
       Blockly.Lua.ORDER_NONE) || '\'\'';
-  var functionName = Blockly.Lua.provideFunction_(
+  const functionName = Blockly.Lua.provideFunction_(
       'text_count',
       ['function ' + Blockly.Lua.FUNCTION_NAME_PLACEHOLDER_
         + '(haystack, needle)',
@@ -311,18 +317,18 @@ Blockly.Lua['text_count'] = function(block) {
         '  return count',
         'end',
       ]);
-  var code = functionName + '(' + text + ', ' + sub + ')';
+  const code = functionName + '(' + text + ', ' + sub + ')';
   return [code, Blockly.Lua.ORDER_HIGH];
 };
 
 Blockly.Lua['text_replace'] = function(block) {
-  var text = Blockly.Lua.valueToCode(block, 'TEXT',
+  const text = Blockly.Lua.valueToCode(block, 'TEXT',
       Blockly.Lua.ORDER_NONE) || '\'\'';
-  var from = Blockly.Lua.valueToCode(block, 'FROM',
+  const from = Blockly.Lua.valueToCode(block, 'FROM',
       Blockly.Lua.ORDER_NONE) || '\'\'';
-  var to = Blockly.Lua.valueToCode(block, 'TO',
+  const to = Blockly.Lua.valueToCode(block, 'TO',
       Blockly.Lua.ORDER_NONE) || '\'\'';
-  var functionName = Blockly.Lua.provideFunction_(
+  const functionName = Blockly.Lua.provideFunction_(
       'text_replace',
       ['function ' + Blockly.Lua.FUNCTION_NAME_PLACEHOLDER_
         + '(haystack, needle, replacement)',
@@ -342,13 +348,13 @@ Blockly.Lua['text_replace'] = function(block) {
         '  return table.concat(buf)',
         'end',
       ]);
-  var code = functionName + '(' + text + ', ' + from + ', ' + to + ')';
+  const code = functionName + '(' + text + ', ' + from + ', ' + to + ')';
   return [code, Blockly.Lua.ORDER_HIGH];
 };
 
 Blockly.Lua['text_reverse'] = function(block) {
-  var text = Blockly.Lua.valueToCode(block, 'TEXT',
+  const text = Blockly.Lua.valueToCode(block, 'TEXT',
       Blockly.Lua.ORDER_NONE) || '\'\'';
-  var code = 'string.reverse(' + text + ')';
+  const code = 'string.reverse(' + text + ')';
   return [code, Blockly.Lua.ORDER_HIGH];
 };
diff --git a/generators/lua/variables.js b/generators/lua/variables.js
index 558117489..c623984ee 100644
--- a/generators/lua/variables.js
+++ b/generators/lua/variables.js
@@ -16,16 +16,16 @@ goog.require('Blockly.Lua');
 
 Blockly.Lua['variables_get'] = function(block) {
   // Variable getter.
-  var code = Blockly.Lua.nameDB_.getName(block.getFieldValue('VAR'),
+  const code = Blockly.Lua.nameDB_.getName(block.getFieldValue('VAR'),
       Blockly.VARIABLE_CATEGORY_NAME);
   return [code, Blockly.Lua.ORDER_ATOMIC];
 };
 
 Blockly.Lua['variables_set'] = function(block) {
   // Variable setter.
-  var argument0 = Blockly.Lua.valueToCode(block, 'VALUE',
+  const argument0 = Blockly.Lua.valueToCode(block, 'VALUE',
       Blockly.Lua.ORDER_NONE) || '0';
-  var varName = Blockly.Lua.nameDB_.getName(
+  const varName = Blockly.Lua.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 26fe5538f..f2849275a 100644
--- a/tests/deps.mocha.js
+++ b/tests/deps.mocha.js
@@ -282,14 +282,14 @@ goog.addDependency('../../generators/javascript/text.js', ['Blockly.JavaScript.t
 goog.addDependency('../../generators/javascript/variables.js', ['Blockly.JavaScript.variables'], ['Blockly.JavaScript'], {'lang': 'es6'});
 goog.addDependency('../../generators/javascript/variables_dynamic.js', ['Blockly.JavaScript.variablesDynamic'], ['Blockly.JavaScript', 'Blockly.JavaScript.variables']);
 goog.addDependency('../../generators/lua.js', ['Blockly.Lua'], ['Blockly.Generator', 'Blockly.inputTypes', 'Blockly.utils.object', 'Blockly.utils.string'], {'lang': 'es6'});
-goog.addDependency('../../generators/lua/colour.js', ['Blockly.Lua.colour'], ['Blockly.Lua']);
-goog.addDependency('../../generators/lua/lists.js', ['Blockly.Lua.lists'], ['Blockly.Lua']);
-goog.addDependency('../../generators/lua/logic.js', ['Blockly.Lua.logic'], ['Blockly.Lua']);
-goog.addDependency('../../generators/lua/loops.js', ['Blockly.Lua.loops'], ['Blockly.Lua']);
-goog.addDependency('../../generators/lua/math.js', ['Blockly.Lua.math'], ['Blockly.Lua']);
-goog.addDependency('../../generators/lua/procedures.js', ['Blockly.Lua.procedures'], ['Blockly.Lua']);
-goog.addDependency('../../generators/lua/text.js', ['Blockly.Lua.texts'], ['Blockly.Lua'], {'lang': 'es5'});
-goog.addDependency('../../generators/lua/variables.js', ['Blockly.Lua.variables'], ['Blockly.Lua']);
+goog.addDependency('../../generators/lua/colour.js', ['Blockly.Lua.colour'], ['Blockly.Lua'], {'lang': 'es6'});
+goog.addDependency('../../generators/lua/lists.js', ['Blockly.Lua.lists'], ['Blockly.Lua'], {'lang': 'es6'});
+goog.addDependency('../../generators/lua/logic.js', ['Blockly.Lua.logic'], ['Blockly.Lua'], {'lang': 'es6'});
+goog.addDependency('../../generators/lua/loops.js', ['Blockly.Lua.loops'], ['Blockly.Lua'], {'lang': 'es6'});
+goog.addDependency('../../generators/lua/math.js', ['Blockly.Lua.math'], ['Blockly.Lua'], {'lang': 'es6'});
+goog.addDependency('../../generators/lua/procedures.js', ['Blockly.Lua.procedures'], ['Blockly.Lua'], {'lang': 'es6'});
+goog.addDependency('../../generators/lua/text.js', ['Blockly.Lua.texts'], ['Blockly.Lua'], {'lang': 'es6'});
+goog.addDependency('../../generators/lua/variables.js', ['Blockly.Lua.variables'], ['Blockly.Lua'], {'lang': 'es6'});
 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'], {'lang': 'es6'});