function listen(name, callback) {
    isValidParameter(name, 'listen()')
    let listeners = SF.listeners[name]
    if (!listeners) {
      listeners = []
      SF.listeners[name] = listeners
    }
    listeners.push(callback)
  }
/*
   * Listen to change of the value for the specified parameter.
   * @param {Symbol} name of the value to listen to. 
   * @param {function} callback to call when the value changes. 
   */
Listen to change of the value for the specified parameter.
@param {Symbol} name of the value to listen to.
@param {function} callback to call when the value changes.
Listen to change of the value for the specified parameter . @param { Symbol } name of the value to listen to . @param { function } callback to call when the value changes .
function listen(name, callback) {
    isValidParameter(name, 'listen()')
    let listeners = SF.listeners[name]
    if (!listeners) {
      listeners = []
      SF.listeners[name] = listeners
    }
    listeners.push(callback)
  }
function listen ( name , callback ) { isValidParameter ( name , 'listen()' ) let listeners = SF . listeners [ name ] if ( ! listeners ) { listeners = [ ] SF . listeners [ name ] = listeners } listeners . push ( callback ) }
Listen to change of the value for the specified parameter.
Listen to change of the value for the specified parameter .