Parses a querystring from the URL fragment

parseQueryString.js

/**
 * Converts the querystring portion of the URL into an object
 * mapping keys to argument values.
 *
 * Examples:
 * - 'foo=bar&baz=quux' -> {foo: 'bar', baz: 'quux'}
 * - 'foo=bar&' -> {foo: 'bar'}
 * - 'foo=bar&baz' -> {foo: 'bar', baz: ''}
 * - 'foo=bar&baz=' -> {foo: 'bar', baz: ''}
 *
 * @param queryString {string}
 * @returns {object}
 */
parseQueryString: function (queryString) {
    return _(decodeURI(queryString).split('&')).map(function (namedVal) {
        var keyValPair = namedVal.split('='), obj = {};
        if ((keyValPair.length === 1 && !keyValPair[0]) ||  // Empty string
            keyValPair.length > 2) {  // Have something like foo=bar=...
            throw new Error('Each "&"-separated substring must either be a key or a key-value pair');
        }
        obj[keyValPair[0]] = keyValPair[1];
        return obj;
    }).reduce(function (memo, keyValPair) {
        return _.extend(memo, keyValPair);
    });
}