feat(Symbol.observable): is no longer polyfilled (#3387)

BREAKING CHANGE: RxJS will no longer be polyfilling Symbol.observable. That should be done by an actual polyfill library. This is to prevent duplication of code, and also to prevent having modules with side-effects in rxjs.

spec/helpers/polyfills.ts

@@ -0,0 +1,11 @@
+if (typeof Symbol !== 'function') {
+  let id = 0;
+  const symbolFn: any = (description: string) =>
+    `Symbol_${id++} ${description} (RxJS Testing Polyfill)`;
+
+  Symbol = symbolFn;
+}
+
+if (!(Symbol as any).observable) {
+  (Symbol as any).observable = Symbol('Symbol.observable polyfill from RxJS Testing');
+}

spec/support/coverage.opts

@@ -1,3 +1,4 @@
+--require spec/helpers/polyfills.ts
 --require spec/helpers/testScheduler-ui.ts
 --ui spec/helpers/testScheduler-ui.ts
 
@@ -6,4 +7,4 @@
 --globals WebSocket,FormData,XDomainRequest,ActiveXObject
 
 --recursive
---timeout 5000
+--timeout 5000

spec/support/default.opts

@@ -1,3 +1,4 @@
+--require .out/spec/helpers/polyfills.ts
 --require .out/spec/helpers/testScheduler-ui.js
 --ui .out/spec/helpers/testScheduler-ui.js
 

spec/support/tests2png.opts

@@ -1,3 +1,4 @@
+--require spec-js/helpers/polyfills.ts
 --require source-map-support/register
 --require spec/helpers/tests2png/diagram-test-runner.ts
 --require spec/helpers/testScheduler-ui.ts
@@ -6,4 +7,4 @@
 --reporter dot
 
 --recursive
---timeout 5000
+--timeout 5000

spec/support/webpack.mocha.config.js

@@ -3,7 +3,7 @@ var path = require('path');
 var glob = require('glob');
 var webpack = require('webpack');
 
-var globPattern = 'spec-js/**/!(mocha.sauce.gruntfile|mocha.sauce.runner|webpack.mocha.config|painter|diagram-test-runner|testScheduler-ui).js';
+var globPattern = 'spec-js/**/!(mocha.sauce.gruntfile|mocha.sauce.runner|webpack.mocha.config|painter|diagram-test-runner|polyfills|testScheduler-ui).js';
 var files = _.map(glob.sync(globPattern), function (x) {
   return path.resolve('./', x);
 });
@@ -18,6 +18,7 @@ module.exports = {
   },
 
   entry: {
+    'browser.polyfills': './spec-js/helpers/polyfills.js',
     'browser.testscheduler': './spec-js/helpers/testScheduler-ui.js',
     'browser.spec': files
   },
@@ -31,4 +32,4 @@ module.exports = {
     new webpack.optimize.CommonsChunkPlugin('browser.common.js'),
     new webpack.IgnorePlugin(/^mocha$/)
   ]
-};
+};

src/internal/symbol/observable.ts

@@ -1,32 +1,13 @@
 import { root } from '../util/root';
 
-export function getSymbolObservable(context: { Symbol: SymbolConstructor; }): symbol {
-  let $$observable: symbol;
-  let Symbol = context.Symbol;
-
-  if (typeof Symbol === 'function') {
-    if (Symbol.observable) {
-      $$observable = Symbol.observable;
-    } else {
-      $$observable = Symbol('observable');
-      Symbol.observable = $$observable;
-    }
-  } else {
-    $$observable = <any>'@@observable';
-  }
-
-  return $$observable;
-}
-
-export const observable = getSymbolObservable(root);
-
-/**
- * @deprecated use observable instead
- */
-export const $$observable = observable;
-
+/** Symbol.observable addition */
+/* Note: This will add Symbol.observable globally for all TypeScript users,
+  however, we are no longer polyfilling Symbol.observable */
 declare global {
   interface SymbolConstructor {
     observable: symbol;
   }
-}
+}
+
+/** Symbol.observable or a string "@@observable". Used for interop */
+export const observable = typeof Symbol === 'function' && Symbol.observable || '@@observable';