44 lines
1.3 KiB
JavaScript
44 lines
1.3 KiB
JavaScript
|
import { Subscriber } from '../Subscriber';
|
||
|
|
import { ArgumentOutOfRangeError } from '../util/ArgumentOutOfRangeError';
|
||
|
|
export function skipLast(count) {
|
||
|
|
return (source) => source.lift(new SkipLastOperator(count));
|
||
|
|
}
|
||
|
|
class SkipLastOperator {
|
||
|
|
constructor(_skipCount) {
|
||
|
|
this._skipCount = _skipCount;
|
||
|
|
if (this._skipCount < 0) {
|
||
|
|
throw new ArgumentOutOfRangeError;
|
||
|
|
}
|
||
|
|
}
|
||
|
|
call(subscriber, source) {
|
||
|
|
if (this._skipCount === 0) {
|
||
|
|
return source.subscribe(new Subscriber(subscriber));
|
||
|
|
}
|
||
|
|
else {
|
||
|
|
return source.subscribe(new SkipLastSubscriber(subscriber, this._skipCount));
|
||
|
|
}
|
||
|
|
}
|
||
|
|
}
|
||
|
|
class SkipLastSubscriber extends Subscriber {
|
||
|
|
constructor(destination, _skipCount) {
|
||
|
|
super(destination);
|
||
|
|
this._skipCount = _skipCount;
|
||
|
|
this._count = 0;
|
||
|
|
this._ring = new Array(_skipCount);
|
||
|
|
}
|
||
|
|
_next(value) {
|
||
|
|
const skipCount = this._skipCount;
|
||
|
|
const count = this._count++;
|
||
|
|
if (count < skipCount) {
|
||
|
|
this._ring[count] = value;
|
||
|
|
}
|
||
|
|
else {
|
||
|
|
const currentIndex = count % skipCount;
|
||
|
|
const ring = this._ring;
|
||
|
|
const oldValue = ring[currentIndex];
|
||
|
|
ring[currentIndex] = value;
|
||
|
|
this.destination.next(oldValue);
|
||
|
|
}
|
||
|
|
}
|
||
|
|
}
|
||
|
|
//# sourceMappingURL=skipLast.js.map
|