take.js 1.14 KB
import { Subscriber } from '../Subscriber';
import { ArgumentOutOfRangeError } from '../util/ArgumentOutOfRangeError';
import { empty } from '../observable/empty';
export function take(count) {
    return (source) => {
        if (count === 0) {
            return empty();
        }
        else {
            return source.lift(new TakeOperator(count));
        }
    };
}
class TakeOperator {
    constructor(total) {
        this.total = total;
        if (this.total < 0) {
            throw new ArgumentOutOfRangeError;
        }
    }
    call(subscriber, source) {
        return source.subscribe(new TakeSubscriber(subscriber, this.total));
    }
}
class TakeSubscriber extends Subscriber {
    constructor(destination, total) {
        super(destination);
        this.total = total;
        this.count = 0;
    }
    _next(value) {
        const total = this.total;
        const count = ++this.count;
        if (count <= total) {
            this.destination.next(value);
            if (count === total) {
                this.destination.complete();
                this.unsubscribe();
            }
        }
    }
}
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