mout/array/flatten.js

Modular Utilities

"use strict";
exports.__esModule = true;
var isArray_1 = require("../lang/isArray");
var append_1 = require("./append");
/*
 * Helper function to flatten to a destination array.
 * Used to remove the need to create intermediate arrays while flattening.
 */
function flattenTo(arr, result, level) {
    if (level === 0) {
        append_1["default"](result, arr);
        return result;
    }
    var value;
    var i = -1;
    var len = arr.length;
    while (++i < len) {
        value = arr[i];
        if (isArray_1["default"](value)) {
            flattenTo(value, result, level - 1);
        }
        else {
            result.push(value);
        }
    }
    return result;
}
/**
 * Recursively flattens an array.
 * A new array containing all the elements is returned.
 * If level is specified, it will only flatten up to that level.
 */
function flatten(arr, level) {
    if (arr == null) {
        return [];
    }
    level = level == null ? -1 : level;
    return flattenTo(arr, [], level);
}
exports["default"] = flatten;