@codibre/fluent-iterable/dist/async-base/merging/merge-iterators.js

Provides LINQ-like fluent api operations for iterables and async iterables (ES2018+).

"use strict";
Object.defineProperty(exports, "__esModule", { value: true });
exports.mergeIterators = mergeIterators;
exports.mergeIterables = mergeIterables;
const get_next_async_iterator_factory_1 = require("./get-next-async-iterator-factory");
async function getNextValue(asyncIteratorsValues) {
    return Promise.race(Array.from(asyncIteratorsValues.values()));
}
async function* mergeIterators(callback, ...iterators) {
    const getNextAsyncIteratorValue = (0, get_next_async_iterator_factory_1.getNextAsyncIteratorFactory)(callback);
    const asyncIteratorsValues = new Map();
    iterators.forEach((it, idx) => asyncIteratorsValues.set(idx, getNextAsyncIteratorValue(it, idx)));
    while (asyncIteratorsValues.size > 0) {
        const { result, index } = await getNextValue(asyncIteratorsValues);
        if (result.done) {
            if (iterators[index].return) {
                iterators[index].return();
            }
            asyncIteratorsValues.delete(index);
        }
        else {
            yield result.value;
            asyncIteratorsValues.set(index, getNextAsyncIteratorValue(iterators[index], index));
        }
    }
}
function mergeIterables(callback, ...iterables) {
    if (callback && typeof callback !== 'function') {
        iterables = [callback, ...iterables];
        callback = undefined;
    }
    return mergeIterators(callback, ...iterables.map((x) => x[Symbol.asyncIterator]()));
}