Migrate core.global.js to named exports (#5451)

This is part of #5153 but is being prioritised because we want remove
the declareLegacyNamespace calls from the core/utils/*.js modules and
then reexport them explicitly via utils.js, and it turns out that
doing so results in the exports object of this module being passed to
Object.freeze - which fails on the global object, which can't be made
non-extensible!

The new name chosen for the former default export is globalThis, since
it is intended to have the same value as the global variable of that
name; see:

https://developer.mozilla.org/en-US/docs/Web/JavaScript/Reference/Global_Objects/globalThis

core/browser_events.js

@@ -14,7 +14,7 @@ goog.module('Blockly.browserEvents');
 goog.module.declareLegacyNamespace();
 
 const Touch = goog.require('Blockly.Touch');
-const global = goog.require('Blockly.utils.global');
+const {globalThis} = goog.require('Blockly.utils.global');
 
 
 /**
@@ -69,7 +69,7 @@ const conditionalBind = function(
   };
 
   const bindData = [];
-  if (global['PointerEvent'] && (name in Touch.TOUCH_MAP)) {
+  if (globalThis['PointerEvent'] && (name in Touch.TOUCH_MAP)) {
     for (let i = 0; i < Touch.TOUCH_MAP[name].length; i++) {
       const type = Touch.TOUCH_MAP[name][i];
       node.addEventListener(type, wrapFunc, false);
@@ -124,7 +124,7 @@ const bind = function(node, name, thisObject, func) {
   };
 
   const bindData = [];
-  if (global['PointerEvent'] && (name in Touch.TOUCH_MAP)) {
+  if (globalThis['PointerEvent'] && (name in Touch.TOUCH_MAP)) {
     for (let i = 0; i < Touch.TOUCH_MAP[name].length; i++) {
       const type = Touch.TOUCH_MAP[name][i];
       node.addEventListener(type, wrapFunc, false);

core/msg.js

@@ -17,16 +17,16 @@
 goog.module('Blockly.Msg');
 goog.module.declareLegacyNamespace();
 
-const global = goog.require('Blockly.utils.global');
+const {globalThis} = goog.require('Blockly.utils.global');
 
 
 /**
  * Exported so that if Blockly is compiled with ADVANCED_COMPILATION,
  * the Blockly.Msg object exists for message files included in script tags.
  */
-if (!global['Blockly']) {
-  global['Blockly'] = {};
+if (!globalThis['Blockly']) {
+  globalThis['Blockly'] = {};
 }
-if (!global['Blockly']['Msg']) {
-  global['Blockly']['Msg'] = exports;
+if (!globalThis['Blockly']['Msg']) {
+  globalThis['Blockly']['Msg'] = exports;
 }

core/touch.js

@@ -16,7 +16,7 @@ goog.module.declareLegacyNamespace();
 /* eslint-disable-next-line no-unused-vars */
 const Gesture = goog.requireType('Blockly.Gesture');
 const internalConstants = goog.require('Blockly.internalConstants');
-const utilsGlobal = goog.require('Blockly.utils.global');
+const {globalThis} = goog.require('Blockly.utils.global');
 const utilsString = goog.require('Blockly.utils.string');
 
 
@@ -26,13 +26,13 @@ const utilsString = goog.require('Blockly.utils.string');
  * @const
  */
 const TOUCH_ENABLED =
-    ('ontouchstart' in utilsGlobal ||
-     !!(utilsGlobal['document'] && document.documentElement &&
+    ('ontouchstart' in globalThis ||
+     !!(globalThis['document'] && document.documentElement &&
         'ontouchstart' in document.documentElement) ||
      // IE10 uses non-standard touch events, so it has a different check.
-     !!(utilsGlobal['navigator'] &&
-        (utilsGlobal['navigator']['maxTouchPoints'] ||
-         utilsGlobal['navigator']['msMaxTouchPoints'])));
+     !!(globalThis['navigator'] &&
+        (globalThis['navigator']['maxTouchPoints'] ||
+         globalThis['navigator']['msMaxTouchPoints'])));
 exports.TOUCH_ENABLED = TOUCH_ENABLED;
 
 /**
@@ -47,7 +47,7 @@ let touchIdentifier_ = null;
  * @type {Object}
  */
 let TOUCH_MAP = {};
-if (utilsGlobal['PointerEvent']) {
+if (globalThis['PointerEvent']) {
   TOUCH_MAP = {
     'mousedown': ['pointerdown'],
     'mouseenter': ['pointerenter'],

core/utils.js

@@ -28,7 +28,7 @@ const Rect = goog.require('Blockly.utils.Rect');
 const WorkspaceSvg = goog.requireType('Blockly.WorkspaceSvg');
 const colourUtils = goog.require('Blockly.utils.colour');
 const deprecation = goog.require('Blockly.utils.deprecation');
-const global = goog.require('Blockly.utils.global');
+const {globalThis} = goog.require('Blockly.utils.global');
 const idGenerator = goog.require('Blockly.utils.idGenerator');
 const internalConstants = goog.require('Blockly.internalConstants');
 const stringUtils = goog.require('Blockly.utils.string');
@@ -433,7 +433,7 @@ const is3dSupported = function() {
   }
   // CC-BY-SA Lorenzo Polidori
   // stackoverflow.com/questions/5661671/detecting-transform-translate3d-support
-  if (!global['getComputedStyle']) {
+  if (!globalThis['getComputedStyle']) {
     return false;
   }
 
@@ -453,7 +453,7 @@ const is3dSupported = function() {
   for (let t in transforms) {
     if (el.style[t] !== undefined) {
       el.style[t] = 'translate3d(1px,1px,1px)';
-      const computedStyle = global['getComputedStyle'](el);
+      const computedStyle = globalThis['getComputedStyle'](el);
       if (!computedStyle) {
         // getComputedStyle in Firefox returns null when Blockly is loaded
         // inside an iframe with display: none.  Returning false and not

core/utils/global.js

@@ -20,7 +20,10 @@ goog.module.declareLegacyNamespace();
  * More info on this implementation here:
  * https://docs.google.com/document/d/1NAeW4Wk7I7FV0Y2tcUFvQdGMc89k2vdgSXInw8_nvCI
  */
-const utilsGlobal = function() {
+exports.globalThis = (function() {  // Not "let globalThis" to avoid shadowing.
+  if (typeof globalThis === 'object') {
+    return globalThis;
+  }
   if (typeof self === 'object') {
     return self;
   }
@@ -31,6 +34,4 @@ const utilsGlobal = function() {
     return global;
   }
   return this;
-}();
-
-exports = utilsGlobal;
+})();

core/utils/useragent.js

@@ -19,7 +19,7 @@
 goog.module('Blockly.utils.userAgent');
 goog.module.declareLegacyNamespace();
 
-const global = goog.require('Blockly.utils.global');
+const {globalThis} = goog.require('Blockly.utils.global');
 
 
 /**
@@ -100,7 +100,7 @@ isGecko = has('Gecko') && !isWebKit && !isIe && !isEdge;
 // https://github.com/google/closure-library/blob/master/closure/goog/labs/useragent/extra.js
 isAndroid = has('Android');
 const maxTouchPoints =
-    global['navigator'] && global['navigator']['maxTouchPoints'];
+    globalThis['navigator'] && globalThis['navigator']['maxTouchPoints'];
 isIPad = has('iPad') || has('Macintosh') && maxTouchPoints > 0;
 isIPod = has('iPod');
 isIPhone = has('iPhone') && !isIPad && !isIPod;
@@ -110,7 +110,7 @@ isMac = has('Macintosh');
 // https://github.com/google/closure-library/blob/master/closure/goog/labs/useragent/device.js
 isTablet = isIPad || (isAndroid && !has('Mobile')) || has('Silk');
 isMobile = !isTablet && (isIPod || isIPhone || isAndroid || has('IEMobile'));
-})((global['navigator'] && global['navigator']['userAgent']) || '');
+})((globalThis['navigator'] && globalThis['navigator']['userAgent']) || '');
 
 /** @const {string} */
 exports.raw = rawUserAgent;

core/workspace_audio.js

@@ -16,7 +16,7 @@ goog.module.declareLegacyNamespace();
 
 /* eslint-disable-next-line no-unused-vars */
 const WorkspaceSvg = goog.requireType('Blockly.WorkspaceSvg');
-const global = goog.require('Blockly.utils.global');
+const {globalThis} = goog.require('Blockly.utils.global');
 const internalConstants = goog.require('Blockly.internalConstants');
 const userAgent = goog.require('Blockly.utils.userAgent');
 
@@ -72,7 +72,7 @@ WorkspaceAudio.prototype.load = function(filenames, name) {
   }
   let audioTest;
   try {
-    audioTest = new global['Audio']();
+    audioTest = new globalThis['Audio']();
   } catch (e) {
     // No browser support for Audio.
     // IE can throw an error even if the Audio object exists.
@@ -84,7 +84,7 @@ WorkspaceAudio.prototype.load = function(filenames, name) {
     const ext = filename.match(/\.(\w+)$/);
     if (ext && audioTest.canPlayType('audio/' + ext[1])) {
       // Found an audio format we can play.
-      sound = new global['Audio'](filename);
+      sound = new globalThis['Audio'](filename);
       break;
     }
   }

generators/javascript.js

@@ -42,7 +42,7 @@ Blockly.JavaScript.addReservedWords(
     // Magic variable.
     'arguments,' +
     // Everything in the current environment (835 items in Chrome, 104 in Node).
-    Object.getOwnPropertyNames(Blockly.utils.global).join(','));
+    Object.getOwnPropertyNames(Blockly.utils.global.globalThis).join(','));
 
 /**
  * Order of operation ENUMs.

scripts/migration/renamings.js

@@ -72,6 +72,9 @@ const renamings = {
         genUid: {module: 'Blockly.utils.idGenerator'},
       }
     },
+    'Blockly.utils.global': {
+      export: 'globalThis',  // Previous default export now named.
+    },
     'Blockly.utils.IdGenerator': {
       module: 'Blockly.utils.idGenerator',
     }

scripts/package/node/core.js

@@ -22,9 +22,10 @@ Blockly.setLocale = function (locale) {
 
 // Override textToDomDocument and provide Node.js alternatives to DOMParser and
 // XMLSerializer.
-if (typeof Blockly.utils.global.document !== 'object') {
-  Blockly.utils.global.DOMParser = require('jsdom/lib/jsdom/living').DOMParser;
-  Blockly.utils.global.XMLSerializer = require('jsdom/lib/jsdom/living').XMLSerializer;
+const globalThis = Blockly.utils.global.globalThis;
+if (typeof globalThis.document !== 'object') {
+  globalThis.DOMParser = require('jsdom/lib/jsdom/living').DOMParser;
+  globalThis.XMLSerializer = require('jsdom/lib/jsdom/living').XMLSerializer;
   var doc = Blockly.utils.xml.textToDomDocument(
     '<xml xmlns="https://developers.google.com/blockly/xml"></xml>');
   Blockly.utils.xml.document = function() {

tests/deps.js

@@ -215,7 +215,7 @@ goog.addDependency('../../core/utils/colour.js', ['Blockly.utils.colour'], [], {
 goog.addDependency('../../core/utils/coordinate.js', ['Blockly.utils.Coordinate'], [], {'lang': 'es6', 'module': 'goog'});
 goog.addDependency('../../core/utils/deprecation.js', ['Blockly.utils.deprecation'], [], {'lang': 'es6', 'module': 'goog'});
 goog.addDependency('../../core/utils/dom.js', ['Blockly.utils.dom'], ['Blockly.utils.userAgent'], {'lang': 'es6', 'module': 'goog'});
-goog.addDependency('../../core/utils/global.js', ['Blockly.utils.global'], [], {'lang': 'es6', 'module': 'goog'});
+goog.addDependency('../../core/utils/global.js', ['Blockly.utils.global'], [], {'module': 'goog'});
 goog.addDependency('../../core/utils/idgenerator.js', ['Blockly.utils.idGenerator'], [], {'lang': 'es6', 'module': 'goog'});
 goog.addDependency('../../core/utils/keycodes.js', ['Blockly.utils.KeyCodes'], [], {'lang': 'es6', 'module': 'goog'});
 goog.addDependency('../../core/utils/math.js', ['Blockly.utils.math'], [], {'lang': 'es6', 'module': 'goog'});