code: function createUriQueryValueMapper (expression) {
    return value => {
      value = value.toString();
      var matches = value.match(expression);
      if (!matches || matches.length === 0) {
        return null;
      }
  
      // the value is the second item, the first is a whole string
      var mappedValue = matches[matches.length - 1];
      try {
        mappedValue = decodeURIComponent(mappedValue);
      } catch (e) {
        // nothing to do
      }
  
      return mappedValue;
    };
  }
docs: Maps query parameter value using the parameters expression.
  @param {RegExp} expression Regular expression to get parameter value.
  @returns {Function} URI query string parameter value mapper function.