AMD module to convert filemode to permissions

README.md

AMD - CONVERTER

This amd module helps to convert file mode to linux permissions (eq. 644 -> rw-r--r--)

How to use it

Create a module and add the converter in the dependency array.
Use the static factory method create to get an instance of the module.
Then call the filemode2Perms method passing the file mode to convert.

define(['converter'], function(converter) {
        console.log(converter.create().filemode2Perms('644'));
});

converter.js

/* 
 * The MIT License
 *
 * Copyright 2013 Eric VILLARD <dev@eviweb.fr>.
 *
 * Permission is hereby granted, free of charge, to any person obtaining a copy
 * of this software and associated documentation files (the "Software"), to deal
 * in the Software without restriction, including without limitation the rights
 * to use, copy, modify, merge, publish, distribute, sublicense, and/or sell
 * copies of the Software, and to permit persons to whom the Software is
 * furnished to do so, subject to the following conditions:
 *
 * The above copyright notice and this permission notice shall be included in
 * all copies or substantial portions of the Software.
 *
 * THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
 * IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
 * FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE
 * AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
 * LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM,
 * OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN
 * THE SOFTWARE.
 */

/**
 * AMD - Converter
 *
 * @author Eric VILLARD <dev@eviweb.fr>
 */
define(function() {
    var converter = function() {
        /**
         * convert a filemode to linux permissions
         * eq. 644 -> rw-r--r--
         *
         * @param {String} mode     filemode to convert
         * @returns {String}        returns permissions
         */
        this.filemode2Perms = function(mode) {
            /**
             * get permission form of a given binary representation
             *
             * @param {String} binary   binary representation
             * @returns {String}        returns permissions
             * @ignore
             */
            function applymask(binary) {
                var permissions = [['-', 'r'], ['-', 'w'], ['-', 'x']],
                        result = '';
                for (var i = 0, l = permissions.length; i < l; i++) {
                    result += permissions[i][binary[i]];
                }
                return result;
            }

            /**
             * enforce a binary representation on three bits
             * this ensure potential leading zeros to be kept
             *
             * @param {String} binary   binary representation
             * @returns {String}        returns three bits binary
             * @ignore
             */
            function pad(binary) {
                return ('000' + binary).substr(-3);
            }

            // split filemode numbers
            var bits = mode.toString().match(/(\d)/g),
                    result = '';
            for (var i = 0, l = bits.length; i < l; i++) {
                var binary = pad(parseInt(bits[i]).toString(2));
                result += applymask(binary);
            }
            return result;
        }
    }

    return {
        /**
         * static factory method
         *
         * @returns {_L1.converter}
         * @static
         */
        create: function() {
            return new converter();
        }
    }
});