work.suroh.tk/node_modules/rxjs/_esm2015/operators/sequenceEqual.js

150 lines
4.8 KiB
JavaScript

import { Subscriber } from '../Subscriber';
import { tryCatch } from '../util/tryCatch';
import { errorObject } from '../util/errorObject';
/**
* Compares all values of two observables in sequence using an optional comparor function
* and returns an observable of a single boolean value representing whether or not the two sequences
* are equal.
*
* <span class="informal">Checks to see of all values emitted by both observables are equal, in order.</span>
*
* <img src="./img/sequenceEqual.png" width="100%">
*
* `sequenceEqual` subscribes to two observables and buffers incoming values from each observable. Whenever either
* observable emits a value, the value is buffered and the buffers are shifted and compared from the bottom
* up; If any value pair doesn't match, the returned observable will emit `false` and complete. If one of the
* observables completes, the operator will wait for the other observable to complete; If the other
* observable emits before completing, the returned observable will emit `false` and complete. If one observable never
* completes or emits after the other complets, the returned observable will never complete.
*
* @example <caption>figure out if the Konami code matches</caption>
* var code = Rx.Observable.from([
* "ArrowUp",
* "ArrowUp",
* "ArrowDown",
* "ArrowDown",
* "ArrowLeft",
* "ArrowRight",
* "ArrowLeft",
* "ArrowRight",
* "KeyB",
* "KeyA",
* "Enter" // no start key, clearly.
* ]);
*
* var keys = Rx.Observable.fromEvent(document, 'keyup')
* .map(e => e.code);
* var matches = keys.bufferCount(11, 1)
* .mergeMap(
* last11 =>
* Rx.Observable.from(last11)
* .sequenceEqual(code)
* );
* matches.subscribe(matched => console.log('Successful cheat at Contra? ', matched));
*
* @see {@link combineLatest}
* @see {@link zip}
* @see {@link withLatestFrom}
*
* @param {Observable} compareTo The observable sequence to compare the source sequence to.
* @param {function} [comparor] An optional function to compare each value pair
* @return {Observable} An Observable of a single boolean value representing whether or not
* the values emitted by both observables were equal in sequence.
* @method sequenceEqual
* @owner Observable
*/
export function sequenceEqual(compareTo, comparor) {
return (source) => source.lift(new SequenceEqualOperator(compareTo, comparor));
}
export class SequenceEqualOperator {
constructor(compareTo, comparor) {
this.compareTo = compareTo;
this.comparor = comparor;
}
call(subscriber, source) {
return source.subscribe(new SequenceEqualSubscriber(subscriber, this.compareTo, this.comparor));
}
}
/**
* We need this JSDoc comment for affecting ESDoc.
* @ignore
* @extends {Ignored}
*/
export class SequenceEqualSubscriber extends Subscriber {
constructor(destination, compareTo, comparor) {
super(destination);
this.compareTo = compareTo;
this.comparor = comparor;
this._a = [];
this._b = [];
this._oneComplete = false;
this.add(compareTo.subscribe(new SequenceEqualCompareToSubscriber(destination, this)));
}
_next(value) {
if (this._oneComplete && this._b.length === 0) {
this.emit(false);
}
else {
this._a.push(value);
this.checkValues();
}
}
_complete() {
if (this._oneComplete) {
this.emit(this._a.length === 0 && this._b.length === 0);
}
else {
this._oneComplete = true;
}
}
checkValues() {
const { _a, _b, comparor } = this;
while (_a.length > 0 && _b.length > 0) {
let a = _a.shift();
let b = _b.shift();
let areEqual = false;
if (comparor) {
areEqual = tryCatch(comparor)(a, b);
if (areEqual === errorObject) {
this.destination.error(errorObject.e);
}
}
else {
areEqual = a === b;
}
if (!areEqual) {
this.emit(false);
}
}
}
emit(value) {
const { destination } = this;
destination.next(value);
destination.complete();
}
nextB(value) {
if (this._oneComplete && this._a.length === 0) {
this.emit(false);
}
else {
this._b.push(value);
this.checkValues();
}
}
}
class SequenceEqualCompareToSubscriber extends Subscriber {
constructor(destination, parent) {
super(destination);
this.parent = parent;
}
_next(value) {
this.parent.nextB(value);
}
_error(err) {
this.parent.error(err);
}
_complete() {
this.parent._complete();
}
}
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