58 lines
1.6 KiB
JavaScript
58 lines
1.6 KiB
JavaScript
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import { Subscriber } from '../Subscriber';
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import { ArgumentOutOfRangeError } from '../util/ArgumentOutOfRangeError';
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import { empty } from '../observable/empty';
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export function takeLast(count) {
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return function takeLastOperatorFunction(source) {
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if (count === 0) {
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return empty();
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}
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else {
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return source.lift(new TakeLastOperator(count));
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}
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};
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}
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class TakeLastOperator {
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constructor(total) {
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this.total = total;
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if (this.total < 0) {
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throw new ArgumentOutOfRangeError;
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}
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}
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call(subscriber, source) {
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return source.subscribe(new TakeLastSubscriber(subscriber, this.total));
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}
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}
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class TakeLastSubscriber extends Subscriber {
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constructor(destination, total) {
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super(destination);
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this.total = total;
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this.ring = new Array();
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this.count = 0;
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}
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_next(value) {
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const ring = this.ring;
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const total = this.total;
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const count = this.count++;
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if (ring.length < total) {
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ring.push(value);
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}
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else {
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const index = count % total;
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ring[index] = value;
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}
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}
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_complete() {
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const destination = this.destination;
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let count = this.count;
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if (count > 0) {
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const total = this.count >= this.total ? this.total : this.count;
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const ring = this.ring;
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for (let i = 0; i < total; i++) {
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const idx = (count++) % total;
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destination.next(ring[idx]);
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}
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}
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destination.complete();
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}
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}
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//# sourceMappingURL=takeLast.js.map
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