lazzy.ts/generators/lazyGroupBy.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.lazyGroupByAsync = exports.lazyGroupBy = void 0;
const chain_1 = require("../chain");
const channel_1 = require("../csp/channel");
function* lazyGroupBy(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)) {
            const channel = new channel_1.Channel();
            yield resultSelector(key, new chain_1.ChainAsync(function () {
                return __asyncGenerator(this, arguments, function* () {
                    while (!channel.isClosed()) {
                        const value = yield __await(channel.take());
                        if (channel_1.isClosed(value)) {
                            break;
                        }
                        yield yield __await(value);
                    }
                });
            }()));
            groups.set(key, channel);
        }
        const channel = groups.get(key);
        channel.put(element);
        x = iterator.next();
    }
    for (const [, channel] of groups) {
        channel.close();
    }
    return x.value;
}
exports.lazyGroupBy = lazyGroupBy;
/**
 * This is temporary solution. Now it is not effective enough...
 * @todo We should refactor this function to work even more lazy!
 */
function lazyGroupByAsync(iterator, keySelector, elementSelector, resultSelector) {
    return __asyncGenerator(this, arguments, function* lazyGroupByAsync_1() {
        const groups = new Map();
        let x = yield __await(iterator.next());
        while (x.done !== true) {
            const key = keySelector(x.value);
            const element = elementSelector(x.value);
            if (!groups.has(key)) {
                groups.set(key, new channel_1.Channel());
            }
            const channel = groups.get(key);
            channel.put(element);
            x = yield __await(iterator.next());
        }
        for (const [key, channel] of groups) {
            channel.close();
            yield yield __await(resultSelector(key, new chain_1.ChainAsync(function () {
                return __asyncGenerator(this, arguments, function* () {
                    while (!channel.isClosed()) {
                        const value = yield __await(channel.take());
                        if (channel_1.isClosed(value)) {
                            break;
                        }
                        yield yield __await(value);
                    }
                });
            }())));
        }
        return yield __await(x.value);
    });
}
exports.lazyGroupByAsync = lazyGroupByAsync;
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