-
Notifications
You must be signed in to change notification settings - Fork 72
/
chain.ts
31 lines (27 loc) · 1.19 KB
/
chain.ts
1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
import { IterableX } from './iterablex';
class ChainIterable<TResult> extends IterableX<TResult> {
private _result: Iterable<TResult>;
constructor(result: Iterable<TResult>) {
super();
this._result = result;
}
[Symbol.iterator]() {
return this._result[Symbol.iterator]();
}
}
/**
* Returns an iterable sequence that is the result of invoking the selector on the source sequence,
* without sharing subscriptions. This operator allows for a fluent style of writing queries that use
* the same sequence multiple times.
* @param {Iterable<TSource>} source Source sequence that will be shared in the selector function.
* @param {function(source: Iterable<TSource>): Iterable<TResult>} selector Selector function which can use
* the source sequence as many times as needed, without sharing subscriptions to the source sequence.
* @returns An iterable sequence that contains the elements of a sequence produced by multicasting the source
* sequence within a selector function.
*/
export function chain<TSource, TResult>(
source: Iterable<TSource>,
selector: (source: Iterable<TSource>) => Iterable<TResult>
): IterableX<TResult> {
return new ChainIterable<TResult>(selector(source));
}