JavaScript class for parsing location.search query attributes

query.values.js

/**
 * Use to parse location.search query attributes.
 * Example usage:
 * var query = new QueryValues(location.search); // "?id=124875&foo=bar&foo=baz"
 * var id = query.attr("id"); // "124875"
 * var foos = query.attrs("foo"); // ["bar", "baz"]
 */
var QueryValues = (function () {
    var LIMIT = 2;
    
    var QueryValues = function (search) {
        this.attrs = {};

        if (search == null || search === "") {
            return;
        }

        search = search.trim();
        if (search.indexOf("?") == 0) {
            search = search.substr(1);
        }

        var pairs = search.split("&");
        pairs.forEach(function (pair) {
            var parts = pair.split('=', LIMIT);
            var value = parts.length >= LIMIT ? parts[1] : null;
            this.addAttr(parts[0], value);
        }, this);
    };

    QueryValues.prototype.addAttr = function (name, value) {
        if (name == null || name === "") {
            return;
        }

        if (value != null) {
            value = decodeURIComponent(value.replace(/\+/g, " "));
        }

        if (this.hasAttr(name)) {
            this.attrs[name].push(value);
        } else {
            this.attrs[name] = [value];
        }
    };

    QueryValues.prototype.hasAttr = function (name) {
        return this.attrs.hasOwnProperty(name);
    };

    QueryValues.prototype.attr = function (name) {
        var attr;
        if (this.hasAttr(name)) {
            attr = this.attrs[name][0];
        }

        return attr;
    };

    QueryValues.prototype.attrs = function (name) {
        var attrs;
        if (this.hasAttr(name)) {
            attrs = this.attrs.slice();
        }

        return attrs;
    };

    return QueryValues;
}());