@reactivex/ix-esnext-esm/asynciterable/operators/groupjoin.js

The Interactive Extensions for JavaScript

import { AsyncIterableX } from '../asynciterablex';
import { createGrouping } from './_grouping';
import { empty } from '../empty';
import { from } from '../from';
import { identity } from '../../util/identity';
import { wrapWithAbort } from './withabort';
import { throwIfAborted } from '../../aborterror';
export class GroupJoinAsyncIterable extends AsyncIterableX {
    constructor(outer, inner, outerSelector, innerSelector, resultSelector) {
        super();
        this._outer = outer;
        this._inner = inner;
        this._outerSelector = outerSelector;
        this._innerSelector = innerSelector;
        this._resultSelector = resultSelector;
    }
    async *[Symbol.asyncIterator](signal) {
        throwIfAborted(signal);
        const map = await createGrouping(this._inner, this._innerSelector, identity, signal);
        for await (const outerElement of wrapWithAbort(this._outer, signal)) {
            const outerKey = await this._outerSelector(outerElement, signal);
            const innerElements = map.has(outerKey) ? map.get(outerKey) : empty();
            yield await this._resultSelector(outerElement, from(innerElements), signal);
        }
    }
}
/**
 * Correlates the elements of two async-iterable sequences based on equality of keys and groups the results.
 *
 * @export
 * @template TOuter The type of the elements of the first async-iterable sequence.
 * @template TInner The type of the elements of the second async-iterable sequence.
 * @template TKey The type of the keys returned by the key selector functions.
 * @template TResult The type of the result elements.
 * @param {AsyncIterable<TInner>} inner The async-enumerable sequence to join to the first sequence.
 * @param {((value: TOuter, signal?: AbortSignal) => TKey | Promise<TKey>)} outerSelector A function to extract the join key from each
 * element of the first sequence.
 * @param {((value: TInner, signal?: AbortSignal) => TKey | Promise<TKey>)} innerSelector A function to extract the join key from each
 * element of the second sequence.
 * @param {((
 *     outer: TOuter,
 *     inner: AsyncIterable<TInner>,
 *     signal?: AbortSignal
 *   ) => TResult | Promise<TResult>)} resultSelector A function to create a result element from an element from the first sequence and a
 * collection of matching elements from the second sequence.
 * @returns {OperatorAsyncFunction<TOuter, TResult>} An operator that returns an async-iterable sequence that contains the result elements
 * that are obtained by performing a grouped join on two sequences.
 */
export function groupJoin(inner, outerSelector, innerSelector, resultSelector) {
    return function groupJoinOperatorFunction(outer) {
        return new GroupJoinAsyncIterable(outer, inner, outerSelector, innerSelector, resultSelector);
    };
}

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