lazzy.ts/generators/groupBy.js

Fast and lightweight library for lazy operations with iterable objects.

"use strict";
var __await = (this && this.__await) || function (v) { return this instanceof __await ? (this.v = v, this) : new __await(v); }
var __asyncGenerator = (this && this.__asyncGenerator) || function (thisArg, _arguments, generator) {
    if (!Symbol.asyncIterator) throw new TypeError("Symbol.asyncIterator is not defined.");
    var g = generator.apply(thisArg, _arguments || []), i, q = [];
    return i = {}, verb("next"), verb("throw"), verb("return"), i[Symbol.asyncIterator] = function () { return this; }, i;
    function verb(n) { if (g[n]) i[n] = function (v) { return new Promise(function (a, b) { q.push([n, v, a, b]) > 1 || resume(n, v); }); }; }
    function resume(n, v) { try { step(g[n](v)); } catch (e) { settle(q[0][3], e); } }
    function step(r) { r.value instanceof __await ? Promise.resolve(r.value.v).then(fulfill, reject) : settle(q[0][2], r); }
    function fulfill(value) { resume("next", value); }
    function reject(value) { resume("throw", value); }
    function settle(f, v) { if (f(v), q.shift(), q.length) resume(q[0][0], q[0][1]); }
};
Object.defineProperty(exports, "__esModule", { value: true });
exports.groupByAsync = exports.groupBy = void 0;
function* groupBy(iterator, keySelector, elementSelector, resultSelector) {
    const groups = new Map();
    let x = iterator.next();
    while (x.done !== true) {
        const key = keySelector(x.value);
        const element = elementSelector(x.value);
        if (!groups.has(key)) {
            groups.set(key, []);
        }
        const group = groups.get(key);
        group === null || group === void 0 ? void 0 : group.push(element);
        x = iterator.next();
    }
    for (const [key, value] of groups) {
        yield resultSelector(key, value);
    }
    return x.value;
}
exports.groupBy = groupBy;
function groupByAsync(iterator, keySelector, elementSelector, resultSelector) {
    return __asyncGenerator(this, arguments, function* groupByAsync_1() {
        const groups = new Map();
        let x = yield __await(iterator.next());
        while (x.done !== true) {
            const value = yield __await(Promise.resolve(x.value));
            const key = keySelector(value);
            const element = elementSelector(value);
            if (!groups.has(key)) {
                groups.set(key, []);
            }
            const group = groups.get(key);
            group === null || group === void 0 ? void 0 : group.push(element);
            x = yield __await(iterator.next());
        }
        for (const [key, value] of groups) {
            yield yield __await(resultSelector(key, value));
        }
        return yield __await(x.value);
    });
}
exports.groupByAsync = groupByAsync;
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