getParameterByNameUsingDefaultValue.js

getParameterByNameUsingDefaultValue.js

/**
 * @copyright 2015 Apple Inc. All rights reserved.
 * @author [email protected]
 */
'use strict';
var cachedValues = {};

/**
 * Returns URL parameter if available, if not returns `defaultValue`
 * @param {String} name			Name of URL parameter to look for
 * @param {*} defaultValue      Default value used if `name` is not found
 * @param {Boolean=false} preventCaching  If true value is never cached, useful for non onetime use parameters
 * @return {*}
 */
module.exports = function getParameterByNameUsingDefaultValue(name, defaultValue, preventCaching) {
    name = name.replace(/[\[]/, "\\[").replace(/[\]]/, "\\]");

    if(preventCaching || !cachedValues.hasOwnProperty(name)) {
        var regex = new RegExp("[\\?&]" + name + "=([^&#]*)");
        var results = regex.exec(location.search);

        var value = (results === null) ? defaultValue : decodeURIComponent(results[1].replace(/\+/g, " "));
        // naive but good enough string to bool conversion
        if(value === "true" || value === "false") value = (value === "true");
        // naive but good enough string to number conversion
        if( !isNaN( parseFloat(value) ) ) value = parseFloat(value);

        cachedValues[name] = value;
    }

    return cachedValues[name];
};