An example of where eslint-plugin-relay with unused-fields misses that fields are used in a function.

RelayUnusedFields.js

// collectConnectionNodes.js - Extracts and filters all nodes from a connection and returns it in a list, preserving the type information.
// @flow
export function collectConnectionNodes<T>(
  connectionObj: ?{
    +edges: ?$ReadOnlyArray<?{
      +node: ?T
    }>
  }
): $ReadOnlyArray<T> {
  if (connectionObj && connectionObj.edges && connectionObj.edges.length > 0) {
    return connectionObj.edges.reduce((acc, curr) => {
      if (curr && curr.node) {
        acc.push(curr.node);
      }

      return acc;
    }, []);
  }

  return [];
}


// SomeComponent.js
// Here's an excerpt of a component using edges/node without it being picked up by the linter

class SomeComponent extends React.Component<Props> {
  ...
  render() {
    const { user } = this.props;
    const friends = collectConnectionNodes(user.friends); // The lint plugin misses that collectConnectionNodes uses edges/node, and reports the fields as unused.
    
    return ...;
  }
}

export default createFragmentContainer(
  SomeComponent,
  {
    user: graphql`
      fragment SomeComponent_user on User {
        friends {
          edges {
            node {
              id
              firstName
            }
          }
        }
      }
    `
  }
);