code: function connectionLineJs_(functionName, typeName) {
    var type = getOptTypesFrom(getRootBlock(), typeName);
    if (type) {
      type = ', ' + type;
    } else {
      type = '';
    }
    return '    this.' + functionName + '(true' + type + ');';
  }
docs: Create JS code required to create a top, bottom, or value connection.
  @param {string} functionName JavaScript function name.
  @param {string} typeName Name of type input.
  @return {string} Line of JavaScript code to create connection.
  @private