blob: 98fe686b670ed1ba25b69b727b1226efb4028d5f [file] [log] [blame]
import { Subscriber } from '../Subscriber';
import { ArgumentOutOfRangeError } from '../util/ArgumentOutOfRangeError';
import { empty } from '../observable/empty';
export function takeLast(count) {
return function takeLastOperatorFunction(source) {
if (count === 0) {
return empty();
}
else {
return source.lift(new TakeLastOperator(count));
}
};
}
class TakeLastOperator {
constructor(total) {
this.total = total;
if (this.total < 0) {
throw new ArgumentOutOfRangeError;
}
}
call(subscriber, source) {
return source.subscribe(new TakeLastSubscriber(subscriber, this.total));
}
}
class TakeLastSubscriber extends Subscriber {
constructor(destination, total) {
super(destination);
this.total = total;
this.ring = new Array();
this.count = 0;
}
_next(value) {
const ring = this.ring;
const total = this.total;
const count = this.count++;
if (ring.length < total) {
ring.push(value);
}
else {
const index = count % total;
ring[index] = value;
}
}
_complete() {
const destination = this.destination;
let count = this.count;
if (count > 0) {
const total = this.count >= this.total ? this.total : this.count;
const ring = this.ring;
for (let i = 0; i < total; i++) {
const idx = (count++) % total;
destination.next(ring[idx]);
}
}
destination.complete();
}
}
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