blob: 5e2c9a6513815a6ea39349b3efeeeab00819592a [file] [log] [blame]
import { Operator } from '../Operator';
import { Observable } from '../Observable';
import { Subscriber } from '../Subscriber';
import { Observer, OperatorFunction } from '../types';
/**
* Returns an Observable that emits whether or not every item of the source satisfies the condition specified.
*
* ## Example
* A simple example emitting true if all elements are less than 5, false otherwise
* ```ts
* import { of } from 'rxjs';
* import { every } from 'rxjs/operators';
*
* of(1, 2, 3, 4, 5, 6).pipe(
* 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);
}
}