RelayJS: How to set initial variables through props

Question

Suppose I have a GraphQL type Echothat repeats everything I request with some decorations. On the other hand, I have a React component that is passed to it echo messagewith some type-specific decorations Echo. How to install initialVariablesfor a component Echo?

I read that setting props installs initialVariables, however this does not work. I tried componentDidMount, but this does not work either.

This Relay Playground indicates that the message is not displayed correctly.

For context

// This component consumes `Echo` type
class Echo extends React.Component {
  componentDidMount() {
    let {relay, message} = this.props; 

    relay.setVariables({
      message
    });
  }

  render() {
    let name = '';
    if (this.props.echo) {
      name = this.props.echo.name;
    }

    return (
      <li>Message: {name}</li>
    );
  }
}

Echo = Relay.createContainer(Echo, {
  // By default `message` is null
  initialVariables: {
    message: null
  },

  fragments: {
    echo: () => Relay.QL`
      fragment on Echo {
        name(message: $message)
      }
    `,
  },
});

This is the type that resolves with an echo.

let EchoType = new GraphQLObjectType({
  name: 'Echo',
  fields: () => ({
    name: {
      type: GraphQLString,
      args: {
        message: {
          type: GraphQLString
        }
      },
      resolve: (echo, {message}) => `Hello, ${message}!`
    }
  })
});

Answer 1

, Relay, message, Echo, , ( ). :

• , Echo:

  <Echo echo={this.props.viewer.echo} defaultMessage="Default"/>
  

• componentDidMount:

  componentDidMount() {
    let {relay, defaultMessage} = this.props; 
  
    relay.setVariables({
      message: defaultMessage
    });
  }
  

( ):

class Echo extends React.Component {
  componentDidMount() {
    let {relay, defaultMessage} = this.props; 

    relay.setVariables({
      message: defaultMessage
    });
  }

  render() {
    let name = '';
    if (this.props.echo) {
      name = this.props.echo.name;
    }

    return (
      <li>Message: {name}</li>
    );
  }
}
Echo = Relay.createContainer(Echo, {
  initialVariables: {
    message: ""
  },
  fragments: {
    echo: () => Relay.QL`
      fragment on Echo {
        name(message: $message)
      }
    `,
  },
});

class EchoApp extends React.Component {
  render() {
    return <ul>
      <Echo echo={this.props.viewer.echo} defaultMessage="Default"/>
    </ul>;
  }
}
EchoApp = Relay.createContainer(EchoApp, {
  fragments: {
    viewer: () => Relay.QL`
      fragment on Viewer {
        echo { ${Echo.getFragment('echo')} },
      }
    `,
  },
});

class EchoRoute extends Relay.Route {
  static routeName = 'Home';
  static queries = {
    viewer: (Component) => Relay.QL`
      query {
        viewer { ${Component.getFragment('viewer')} },
      }
    `,
  };
}

ReactDOM.render(
  <Relay.RootContainer
    Component={EchoApp}
    route={new EchoRoute()}
  />,
  mountNode
);