refactor(Symbol): introduce unified Symbol module

closes ReactiveX#844

spec/observables/from-spec.js

@@ -2,7 +2,7 @@
 var Rx = require('../../dist/cjs/Rx');
 var Promise = require('promise');
 var Observable = Rx.Observable;
-var $$iterator = require('../../dist/cjs/util/Symbol_iterator').$$iterator;
+var $$iterator = require('../../dist/cjs/util/SymbolShim').SymbolShim.iterator;
 
 describe('Observable.from', function () {
   it('should enumerate an Array', function (done) {

src/Observable.ts

@@ -5,7 +5,7 @@ import {Subscriber} from './Subscriber';
 import {Subscription} from './Subscription';
 import {root} from './util/root';
 import {CoreOperators } from './CoreOperators';
-import {$$observable} from './util/Symbol_observable';
+import {SymbolShim} from './util/SymbolShim';
 import {GroupedObservable} from './operators/groupBy-support';
 import {ConnectableObservable} from './observable/ConnectableObservable';
 import {Subject} from './Subject';
@@ -67,7 +67,7 @@ export class Observable<T> implements CoreOperators<T>  {
    * @returns {Observable} this instance of the observable
    * @description an interop point defined by the es7-observable spec https://github.com/zenparsing/es-observable
    */
-  [$$observable]() {
+  [SymbolShim.observable]() {
     return this;
   }
 

src/observable/IteratorObservable.ts

@@ -2,7 +2,7 @@ import {Scheduler} from '../Scheduler';
 import {Observable} from '../Observable';
 
 import {root} from '../util/root';
-import {$$iterator} from '../util/Symbol_iterator';
+import {SymbolShim} from '../util/SymbolShim';
 import {tryCatch} from '../util/tryCatch';
 import {errorObject} from '../util/errorObject';
 
@@ -105,7 +105,7 @@ class StringIterator {
               private idx: number = 0,
               private len: number = str.length) {
   }
-  [$$iterator]() { return (this); }
+  [SymbolShim.iterator]() { return (this); }
   next() {
     return this.idx < this.len ? {
         done: false,
@@ -122,7 +122,7 @@ class ArrayIterator {
               private idx: number = 0,
               private len: number = toLength(arr)) {
   }
-  [$$iterator]() { return this; }
+  [SymbolShim.iterator]() { return this; }
   next() {
     return this.idx < this.len ? {
         done: false,
@@ -135,7 +135,7 @@ class ArrayIterator {
 }
 
 function getIterator(obj: any) {
-  const i = obj[$$iterator];
+  const i = obj[SymbolShim.iterator];
   if (!i && typeof obj === 'string') {
     return new StringIterator(obj);
   }
@@ -145,7 +145,7 @@ function getIterator(obj: any) {
   if (!i) {
     throw new TypeError('Object is not iterable');
   }
-  return obj[$$iterator]();
+  return obj[SymbolShim.iterator]();
 }
 
 const maxSafeInteger = Math.pow(2, 53) - 1;

src/observable/from.ts

@@ -3,8 +3,7 @@ import {IteratorObservable} from'./IteratorObservable';
 import {ArrayObservable} from './fromArray';
 
 import {Scheduler} from '../Scheduler';
-import {$$observable} from '../util/Symbol_observable';
-import {$$iterator} from '../util/Symbol_iterator';
+import {SymbolShim} from '../util/SymbolShim';
 import {Observable} from '../Observable';
 import {Subscriber} from '../Subscriber';
 import {ObserveOnSubscriber} from '../operators/observeOn-support';
@@ -23,12 +22,12 @@ export class FromObservable<T> extends Observable<T> {
         return new ArrayObservable(ish, scheduler);
       } else if (typeof ish.then === 'function') {
         return new PromiseObservable(ish, scheduler);
-      } else if (typeof ish[$$observable] === 'function') {
+      } else if (typeof ish[SymbolShim.observable] === 'function') {
         if (ish instanceof Observable) {
           return ish;
         }
         return new FromObservable(ish, scheduler);
-      } else if (typeof ish[$$iterator] === 'function') {
+      } else if (typeof ish[SymbolShim.iterator] === 'function') {
         return new IteratorObservable(ish, null, null, scheduler);
       }
     }
@@ -40,9 +39,9 @@ export class FromObservable<T> extends Observable<T> {
     const ish = this.ish;
     const scheduler = this.scheduler;
     if (scheduler === immediate) {
-      return ish[$$observable]().subscribe(subscriber);
+      return ish[SymbolShim.observable]().subscribe(subscriber);
     } else {
-      return ish[$$observable]().subscribe(new ObserveOnSubscriber(subscriber, scheduler, 0));
+      return ish[SymbolShim.observable]().subscribe(new ObserveOnSubscriber(subscriber, scheduler, 0));
     }
   }
 }

src/operators/zip-support.ts

@@ -6,7 +6,7 @@ import {tryCatch} from '../util/tryCatch';
 import {errorObject} from '../util/errorObject';
 import {OuterSubscriber} from '../OuterSubscriber';
 import {subscribeToResult} from '../util/subscribeToResult';
-import {$$iterator} from '../util/Symbol_iterator';
+import {SymbolShim} from '../util/SymbolShim';
 
 const isArray = Array.isArray;
 
@@ -43,8 +43,8 @@ export class ZipSubscriber<T, R> extends Subscriber<T> {
     const index = this.index++;
     if (isArray(value)) {
       iterators.push(new StaticArrayIterator(value));
-    } else if (typeof value[$$iterator] === 'function') {
-      iterators.push(new StaticIterator(value[$$iterator]()));
+    } else if (typeof value[SymbolShim.iterator] === 'function') {
+      iterators.push(new StaticIterator(value[SymbolShim.iterator]()));
     } else {
       iterators.push(new ZipBufferIterator(this.destination, this, value, index));
     }
@@ -158,7 +158,7 @@ class StaticArrayIterator<T> implements LookAheadIterator<T> {
     this.length = array.length;
   }
 
-  [$$iterator]() {
+  [SymbolShim.iterator]() {
     return this;
   }
 
@@ -189,7 +189,7 @@ class ZipBufferIterator<T, R> extends OuterSubscriber<T, R> implements LookAhead
     super(destination);
   }
 
-  [$$iterator]() {
+  [SymbolShim.iterator]() {
     return this;
   }
 

src/util/Symbol_iterator.ts → src/util/SymbolShim.ts

@@ -1,36 +1,48 @@
-import {root} from './root';
-
-if (!root.Symbol) {
-  root.Symbol = {};
-}
-
-if (!root.Symbol.iterator) {
-  if (typeof root.Symbol.for === 'function') {
-    root.Symbol.iterator = root.Symbol.for('iterator');
-  } else if (root.Set && typeof new root.Set()['@@iterator'] === 'function') {
-    // Bug for mozilla version
-    root.Symbol.iterator = '@@iterator';
-  } else if (root.Map) {
-    // es6-shim specific logic
-    let keys = Object.getOwnPropertyNames(root.Map.prototype);
-    for (let i = 0; i < keys.length; ++i) {
-      let key = keys[i];
-      if (key !== 'entries' && key !== 'size' && root.Map.prototype[key] === root.Map.prototype['entries']) {
-        root.Symbol.iterator = key;
-        break;
-      }
-    }
-  } else {
-    root.Symbol.iterator = '@@iterator';
-  }
-}
-
-export const $$iterator = root.Symbol.iterator;
-
-// // Shim in iterator support
-// export var $iterator$ = (typeof Symbol === 'function' && Symbol.iterator) || '_es6shim_iterator_';
-
-// // Bug for mozilla version
-// if (root.Set && typeof new root.Set()['@@iterator'] === 'function') {
-//     $iterator$ = '@@iterator';
-// }
+import {root} from './root';
+
+if (!root.Symbol) {
+  root.Symbol = {};
+}
+
+if (!root.Symbol.observable) {
+  if (typeof root.Symbol.for === 'function') {
+    root.Symbol.observable = root.Symbol.for('observable');
+  } else {
+    root.Symbol.observable = '@@observable';
+  }
+}
+
+if (!root.Symbol.iterator) {
+  if (typeof root.Symbol.for === 'function') {
+    root.Symbol.iterator = root.Symbol.for('iterator');
+  } else if (root.Set && typeof new root.Set()['@@iterator'] === 'function') {
+    // Bug for mozilla version
+    root.Symbol.iterator = '@@iterator';
+  } else if (root.Map) {
+    // es6-shim specific logic
+    let keys = Object.getOwnPropertyNames(root.Map.prototype);
+    for (let i = 0; i < keys.length; ++i) {
+      let key = keys[i];
+      if (key !== 'entries' && key !== 'size' && root.Map.prototype[key] === root.Map.prototype['entries']) {
+        root.Symbol.iterator = key;
+        break;
+      }
+    }
+  } else {
+    root.Symbol.iterator = '@@iterator';
+  }
+}
+
+if (!root.Symbol.dispose) {
+  if (typeof root.Symbol.for === 'function') {
+    root.Symbol.dispose = root.Symbol.for('dispose');
+  } else {
+    root.Symbol.dispose = '@@dispose';
+  }
+}
+
+export module SymbolShim {
+  export const observable: symbol = root.Symbol.observable;
+  export const iterator: symbol = root.Symbol.iterator;
+  export const dispose: symbol = root.Symbol.dispose;
+};

src/util/subscribeToResult.ts

@@ -1,7 +1,6 @@
 import {Subscriber} from '../Subscriber';
 import {Observable} from '../Observable';
-import {$$iterator} from '../util/Symbol_iterator';
-import {$$observable} from '../util/Symbol_observable';
+import {SymbolShim} from '../util/SymbolShim';
 import {Subscription} from '../Subscription';
 import {InnerSubscriber} from '../InnerSubscriber';
 import {OuterSubscriber} from '../OuterSubscriber';
@@ -47,7 +46,7 @@ export function subscribeToResult<T, R>(outerSubscriber: OuterSubscriber<T, R>,
       setTimeout(() => { throw err; });
     });
     return destination;
-  } else if (typeof result[$$iterator] === 'function') {
+  } else if (typeof result[SymbolShim.iterator] === 'function') {
     for (let item of result) {
       destination.next(item);
       if (destination.isUnsubscribed) {
@@ -57,8 +56,8 @@ export function subscribeToResult<T, R>(outerSubscriber: OuterSubscriber<T, R>,
     if (!destination.isUnsubscribed) {
       destination.complete();
     }
-  } else if (typeof result[$$observable] === 'function') {
-    const obs = result[$$observable]();
+  } else if (typeof result[SymbolShim.observable] === 'function') {
+    const obs = result[SymbolShim.observable]();
     if (typeof obs.subscribe !== 'function') {
       destination.error('invalid observable');
     } else {