@mightyplow/jslib/array/chunkedForEach.js

js helpers library

var _this = this;

function _toConsumableArray(arr) { if (Array.isArray(arr)) { for (var i = 0, arr2 = Array(arr.length); i < arr.length; i++) { arr2[i] = arr[i]; } return arr2; } else { return Array.from(arr); } }

import checkArray from './_checkArray';

var processViaPostMessage = function processViaPostMessage(ar, fn, resolve, chunkSize, msg) {
    var values = [].concat(_toConsumableArray(ar));

    window.addEventListener('message', execNext);
    postMessage(msg, '*');

    function execNext(_ref) {
        var data = _ref.data;

        if (data !== msg) {
            return;
        }

        if (values.length) {
            values.splice(0, chunkSize).forEach(fn);
            postMessage(msg, '*');
        } else {
            resolve();
            window.removeEventListener('message', execNext);
        }
    }
};

var processViaTimeout = function processViaTimeout(ar, fn, resolve, chunkSize, msg) {
    if (ar.length) {
        ar.slice(0, chunkSize).forEach(fn);
        setTimeout(processViaTimeout.bind(_this, ar.slice(chunkSize), fn, resolve, chunkSize, msg));
    } else {
        resolve();
    }
};

var createSplitMessage = function createSplitMessage() {
    return 'FOR_EACH_SPLIT_' + Math.floor(Math.random() * 10000);
};

var process = typeof postMessage === 'undefined' ? processViaPostMessage : processViaTimeout;

/**
 * Splits an array into chunks and breaks the execution queue to ensure reactivity.
 *
 * @memberOf array
 * @param {Array} ar
 * @param {function} fn
 * @param {number} chunkSize
 * @return {Promise}
 */
var chunkedForEach = function chunkedForEach() {
    var ar = arguments.length > 0 && arguments[0] !== undefined ? arguments[0] : [];
    var fn = arguments.length > 1 && arguments[1] !== undefined ? arguments[1] : Function.prototype;
    var chunkSize = arguments.length > 2 && arguments[2] !== undefined ? arguments[2] : 1;

    checkArray(ar);

    return new Promise(function (resolve, reject) {
        process(ar, fn, resolve, chunkSize, createSplitMessage());
    });
};

export default chunkedForEach;