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