fix: loading messages from script tags. (google#6184)

* fix: loading messages in the browser

* chore: fix comment

* fix: change unwrapped message files to write to a new object, rather than Blockly.Msg

* fix: fixup exports

* fix: PR comments

* fix: change to use for-in loop

* fix: ES6 compatibility and formatting

scripts/gulpfiles/package_tasks.js

@@ -29,12 +29,12 @@ const TEMPLATE_DIR = 'scripts/package/templates';
  * @param {string} namespace The export namespace.
  * @param {Array<Object>} dependencies An array of dependencies to inject.
  */
-function packageUMD(namespace, dependencies) {
+function packageUMD(namespace, dependencies, template = 'umd.template') {
   return gulp.umd({
     dependencies: function () { return dependencies; },
     namespace: function () { return namespace; },
     exports: function () { return namespace; },
-    template: path.join(TEMPLATE_DIR, 'umd.template')
+    template: path.join(TEMPLATE_DIR, template)
   });
 };
 
@@ -321,13 +321,10 @@ function packageLocales() {
   // Remove references to goog.provide and goog.require.
   return gulp.src(`${BUILD_DIR}/msg/js/*.js`)
       .pipe(gulp.replace(/goog\.[^\n]+/g, ''))
-      .pipe(gulp.insert.prepend(`
-      var Blockly = {};Blockly.Msg={};`))
-      .pipe(packageUMD('Blockly.Msg', [{
-          name: 'Blockly',
-          amd: '../core',
-          cjs: '../core',
-        }]))
+      .pipe(packageUMD(
+        'Blockly.Msg',
+        [{name: 'Blockly'}],
+        'umd-msg.template'))
       .pipe(gulp.dest(`${RELEASE_DIR}/msg`));
 };
 

scripts/i18n/create_messages.py

@@ -41,7 +41,7 @@ def load_constants(filename):
   for key in constant_defs:
     value = constant_defs[key]
     value = value.replace('"', '\\"')
-    constants_text += u'\nBlockly.Msg["{0}"] = \"{1}\";'.format(
+    constants_text += u'\nmessages["{0}"] = \"{1}\";'.format(
         key, value)
   return constants_text
 
@@ -88,7 +88,7 @@ def main():
       os.curdir, args.source_synonym_file))
 
   # synonym_defs is also being sorted to ensure the same order is kept
-  synonym_text = '\n'.join([u'Blockly.Msg["{0}"] = Blockly.Msg["{1}"];'
+  synonym_text = '\n'.join([u'messages["{0}"] = messages["{1}"];'
       .format(key, synonym_defs[key]) for key in sorted(synonym_defs)])
 
   # Read in constants file, which must be output in every language.
@@ -123,6 +123,8 @@ def main():
 
 'use strict';
 
+const messages = Object.create(null);
+
 """.format(target_lang.replace('-', '.')))
         # For each key in the source language file, output the target value
         # if present; otherwise, output the source language value with a
@@ -136,7 +138,7 @@ def main():
             value = source_defs[key]
             comment = '  // untranslated'
           value = value.replace('"', '\\"')
-          outfile.write(u'Blockly.Msg["{0}"] = "{1}";{2}\n'
+          outfile.write(u'messages["{0}"] = "{1}";{2}\n'
               .format(key, value, comment))
 
         # Announce any keys defined only for target language.

scripts/package/templates/umd-msg.template

@@ -0,0 +1,16 @@
+/* eslint-disable */
+;(function(root, factory) {
+  if (typeof define === 'function' && define.amd) { // AMD
+    define(<%= amd %>, factory);
+  } else if (typeof exports === 'object') { // Node.js
+    module.exports = factory();
+  } else { // Browser
+    var messages = factory();
+    for (var key in messages) {
+      root.<%= namespace %>[key] = messages[key];
+    }
+  }
+}(this, function() {
+<%= contents %>
+return messages;
+}));