# ServiceExtensionResponse.error constructor

ServiceExtensionResponse.error(int errorCode, String errorDetail)

Creates an error response to a service protocol extension RPC.

Requires `errorCode` to be invalidParams or between extensionErrorMin and extensionErrorMax. Requires `errorDetail` to be a JSON object encoded as a string. When forming the JSON-RPC message `errorDetail` will be inlined directly.

## Implementation

    ServiceExtensionResponse.error(int errorCode, String errorDetail)
        : _result = null,
          _errorCode = errorCode,
          _errorDetail = errorDetail {
      _validateErrorCode(_errorCode);
      if (_errorDetail is! String) {
        throw new ArgumentError.value(
            _errorDetail, "errorDetail", "Must be a String");
      }
    }