Angular WYSIWYG utils

wysiwyg.utils.js

/**
 * WYSIWYG utils
 *
 * @namespace WYSIWYGUtils
 */
(function() {

    "use strict";

    angular
        .module('wysiwyg.utils', [])
        .factory('WYSIWYGUtils', WYSIWYGUtils);

    /**
     * @namespace WYSIWYGUtils
     * @desc Simple wysiwyg editor utilities.
     * @memberOf WYSIWYGUtils
     */
    function WYSIWYGUtils() {

        return {

            /**
             * Decreases all occurrences of font-size by the provide factor for the given html string
             * @param html HTML string to search for font-size attributes
             * @param factor Value to subtract on the font-size
             * @returns {String} html string with updated font-size value
             */
            decreaseFontSize: function (html, factor) {
                if(!html || !factor){
                    return "";
                }
                return applyExpression(html, factor, subtract);
            },

            /**
             * Increases all occurrences of font-size by the provide factor for the given html string
             * @param html HTML string to search for font-size attributes
             * @param factor Value to add on the font-size
             * @returns {String} html string with updated font-size value
             */
            increaseFontSize: function (html, factor) {
                if(!html || !factor){
                    return "";
                }
                return applyExpression(html, factor, add);
            }
        };

        /**
         * Apply regex expression
         * @param html html string
         * @param factor value to add or subtract in font-size
         * @param operation add or subtract function
         * @returns {String} html string with updated font-size value
         */
        function applyExpression(html, factor, operation) {

            // $1 == (font-size:)
            // $2 == (value \m/)
            // $3 == (px;)
            var expression = /(font-size:\s*)(\d+)(\s*px;)/g;

            return html.replace(expression,  function(match, $1, $2, $3){
                return $1 + operation(parseInt($2), factor) + $3;
            });
        }

        /**
         * Add value
         * @param value value
         * @param factor amount to add
         * @returns {Integer} sum of value plus factor
         */
        function add(value, factor) {
            return value + factor;
        }

        /**
         * Subtract value
         * @param value value
         * @param factor amount to subtract
         * @returns {Integer} sum of value minus factor
         */
        function subtract(value, factor) {
            return value - factor;
        }

    }
})();

wysiwyg.utils.spec.js

"use strict";

describe('wysiwyg.utils factory', function() {

    var WYSIWYGUtils;

    // Before each test load our wysiwyg.utils module
    beforeEach(module('wysiwyg.utils'));
    // beforeEach(angular.mock.module('wysiwyg.utils'));

    // Before each test set our injected WYSIWYGUtils factory (_WYSIWYGUtils_) to our local WYSIWYGUtils variable
    beforeEach(inject(function(_WYSIWYGUtils_){
        WYSIWYGUtils = _WYSIWYGUtils_;
    }));

    // A simple test to verify the WYSIWYGUtils factory exists
    it('should exist', function() {
        expect(WYSIWYGUtils).toBeDefined();
    });

    it('should increase the font-size value by a factor of 2', function() {

        var factor = 2;
        var html = '<span style="font-size: 6px;"></span><span style="font-size: 10px;"></span>';
        var expected = '<span style="font-size: 8px;"></span><span style="font-size: 12px;"></span>';

        expect(expected).toEqual(WYSIWYGUtils.increaseFontSize(html, factor));
        // expect(expected).toBe('technical death metal \m/'); // this test should fail
    });
});