feat(every): add higher-order lettable version of every

Author: benlesh

src/operator/every.ts

@@ -1,7 +1,6 @@
-import { Operator } from '../Operator';
-import { Observer } from '../Observer';
+
 import { Observable } from '../Observable';
-import { Subscriber } from '../Subscriber';
+import { every as higherOrder } from '../operators';
 
 /**
  * Returns an Observable that emits whether or not every item of the source satisfies the condition specified.
@@ -19,56 +18,5 @@ import { Subscriber } from '../Subscriber';
  */
 export function every<T>(this: Observable<T>, predicate: (value: T, index: number, source: Observable<T>) => boolean,
                          thisArg?: any): Observable<boolean> {
-  return this.lift(new EveryOperator(predicate, thisArg, this));
-}
-
-class EveryOperator<T> implements Operator<T, boolean> {
-  constructor(private predicate: (value: T, index: number, source: Observable<T>) => boolean,
-              private thisArg?: any,
-              private source?: Observable<T>) {
-  }
-
-  call(observer: Subscriber<boolean>, source: any): any {
-    return source.subscribe(new EverySubscriber(observer, this.predicate, this.thisArg, this.source));
-  }
-}
-
-/**
- * We need this JSDoc comment for affecting ESDoc.
- * @ignore
- * @extends {Ignored}
- */
-class EverySubscriber<T> extends Subscriber<T> {
-  private index: number = 0;
-
-  constructor(destination: Observer<boolean>,
-              private predicate: (value: T, index: number, source: Observable<T>) => boolean,
-              private thisArg: any,
-              private source?: Observable<T>) {
-    super(destination);
-    this.thisArg = thisArg || this;
-  }
-
-  private notifyComplete(everyValueMatch: boolean): void {
-    this.destination.next(everyValueMatch);
-    this.destination.complete();
-  }
-
-  protected _next(value: T): void {
-    let result = false;
-    try {
-      result = this.predicate.call(this.thisArg, value, this.index++, this.source);
-    } catch (err) {
-      this.destination.error(err);
-      return;
-    }
-
-    if (!result) {
-      this.notifyComplete(false);
-    }
-  }
-
-  protected _complete(): void {
-    this.notifyComplete(true);
-  }
-}
+  return higherOrder(predicate, thisArg)(this);
+}

src/operators/every.ts

@@ -0,0 +1,75 @@
+import { Operator } from '../Operator';
+import { Observer } from '../Observer';
+import { Observable } from '../Observable';
+import { Subscriber } from '../Subscriber';
+import { OperatorFunction } from '../interfaces';
+
+/**
+ * Returns an Observable that emits whether or not every item of the source satisfies the condition specified.
+ *
+ * @example <caption>A simple example emitting true if all elements are less than 5, false otherwise</caption>
+ *  Observable.of(1, 2, 3, 4, 5, 6)
+ *     .every(x => x < 5)
+ *     .subscribe(x => console.log(x)); // -> false
+ *
+ * @param {function} predicate A function for determining if an item meets a specified condition.
+ * @param {any} [thisArg] Optional object to use for `this` in the callback.
+ * @return {Observable} An Observable of booleans that determines if all items of the source Observable meet the condition specified.
+ * @method every
+ * @owner Observable
+ */
+export function every<T>(predicate: (value: T, index: number, source: Observable<T>) => boolean,
+                         thisArg?: any): OperatorFunction<T, boolean> {
+  return (source: Observable<T>) => source.lift(new EveryOperator(predicate, thisArg, source));
+}
+
+class EveryOperator<T> implements Operator<T, boolean> {
+  constructor(private predicate: (value: T, index: number, source: Observable<T>) => boolean,
+              private thisArg?: any,
+              private source?: Observable<T>) {
+  }
+
+  call(observer: Subscriber<boolean>, source: any): any {
+    return source.subscribe(new EverySubscriber(observer, this.predicate, this.thisArg, this.source));
+  }
+}
+
+/**
+ * We need this JSDoc comment for affecting ESDoc.
+ * @ignore
+ * @extends {Ignored}
+ */
+class EverySubscriber<T> extends Subscriber<T> {
+  private index: number = 0;
+
+  constructor(destination: Observer<boolean>,
+              private predicate: (value: T, index: number, source: Observable<T>) => boolean,
+              private thisArg: any,
+              private source?: Observable<T>) {
+    super(destination);
+    this.thisArg = thisArg || this;
+  }
+
+  private notifyComplete(everyValueMatch: boolean): void {
+    this.destination.next(everyValueMatch);
+    this.destination.complete();
+  }
+
+  protected _next(value: T): void {
+    let result = false;
+    try {
+      result = this.predicate.call(this.thisArg, value, this.index++, this.source);
+    } catch (err) {
+      this.destination.error(err);
+      return;
+    }
+
+    if (!result) {
+      this.notifyComplete(false);
+    }
+  }
+
+  protected _complete(): void {
+    this.notifyComplete(true);
+  }
+}

src/operators/index.ts

@@ -20,6 +20,7 @@ export { dematerialize } from './dematerialize';
 export { distinctUntilChanged } from './distinctUntilChanged';
 export { distinctUntilKeyChanged } from './distinctUntilKeyChanged';
 export { elementAt } from './elementAt';
+export { every } from './every';
 export { filter } from './filter';
 export { ignoreElements } from './ignoreElements';
 export { map } from './map';