area51/lib/collections/array-util.js

Experimental prototypes of alien things built in JavaScript. The bits may end up living in a different package.

"use strict";

Object.defineProperty(exports, "__esModule", {
	value: true
});
exports.swap = swap;
exports.remove = remove;
exports.add = add;
exports.insert = insert;
exports.reverse = reverse;
exports.copy = copy;
exports.clone = clone;

var stringify = Object.prototype.toString;

function swap(array, i, j) {
	var old = array[i];
	array[i] = array[j];
	array[j] = old;
}

function remove(array, index) {
	return array.splice(index, 1);
}

function add(array, item, index) {
	index = index || array.length;
	array[index] = item;

	return array;
}

function insert(array, index, item) {
	array.splice(index, 0, item);

	return array;
}

function reverse(array, startIndex, length) {
	var i = startIndex || 0,
	    j = (length || array.length) - 1;

	for (; i < j; i++, j--) {
		var old = array[i];
		array[i] = array[j];
		array[j] = old;
	}
}

/**
 * Copies an array to another array. The way an array is copied can be changed by providing
 * a copy function that accepts the source array, current index, destination array, destination index.
 *
 * @example
 * 		var copy = require("kit/lib/copy"),
 *			arrayCopy = require("kit/lib/array-copy");
 *		
 *      // array copy that clones objects
 *		arrayCopy(["one", {test: "value"}], 0, [], 0, null, copy); 
 *
 * 
 *
 * @param {Array} source  The array that hold the values that will be copied.
 * @param {Number} [sourceIndex] The index position that the sourceIndex should start.
 * @param {Array} destination The array that the values will be copied to.
 * @param {Number} [destinationIndex]  The position of the destination array that the copy should start at.
 * @param {Number} [length] The number of items that should be copied.
 * @param {Function} [copy] The function that will override the copy action.  
 */

function copy(source, sourceIndex, destination, destinationIndex, length, copy) {
	var from = Object(source),
	    i = sourceIndex || 0,
	    c = destinationIndex || 0,
	    l = length || from.length,
	    to = destination;

	if (l > from.length) l = from.length;

	if (!to) to = new Array(c + (l - i));else to.length = c + (l - i);

	if (copy) {
		for (; i < l; i++) {
			copy(from, c, to, i);

			c++;
		}

		return to;
	}

	for (; i < l; i++) {
		to[c] = from[i];
		c++;
	}

	return to;
}

;

function clone(array, length) {
	var clone = [].concat(array);
	if (length) clone.length = length;
	return clone;
}