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QueryRenderer

A QueryRenderer is a React Component at the root of a Relay component tree. It takes a query, fetches the given query, and uses the render prop to render the resulting data.

As React components, QueryRenderers can be rendered anywhere that a React component can be rendered, i.e. not just at the top level but within other components or containers; for example, to lazily fetch additional data for a popover.

However, a QueryRenderer will not start loading its data until it is mounted, so nested QueryRenderer components can lead to request waterfalls if used unnecessarily.

Props

• environment: The Relay Environment
• query: The graphql tagged query. Note: To enable compatibility mode, relay-compiler enforces the query to be named as <FileName>Query.
• variables: Object containing set of variables to pass to the GraphQL query, i.e. a mapping from variable name to value. Note: If a new set of variables if passed, the QueryRenderer will re-fetch the query.
• render: Function of type ({error, props}) => React.Node. The output of this function will be rendered by the QueryRenderer.
  • props: Object containing data obtained from the query; the shape of this object will match the shape of the query. If this object is not defined, it means that the data is still being fetched.
  • error: Error will be defined if an error has occurred while fetching the query.

Example

// Example.js
import React from 'react';
import { QueryRenderer, graphql } from 'react-relay';

class Example extends React.Component {
  render() {
    return (
      <QueryRenderer
        environment={environment}
        query={graphql`
          query ExampleQuery($pageID: ID!) {
            page(id: $pageID) {
              name
            }
          }
        `}
        variables={{
          pageID: '110798995619330',
        }}
        render={({error, props}) => {
          if (error) {
            return <div>{error.message}</div>;
          } else if (props) {
            return <div>{props.page.name} is great!</div>;
          }
          return <div>Loading</div>;
        }}
      />
    );
  }
}