how to skip request in `useLazyLoadQuery`

Question

How I can skip request/query in useLazyLoadQuery.

import { useLazyLoadQuery } from 'react-relay/hooks';

const id = props.selectedId // id can be a number or null
const user = useLazyLoadQuery(query, {id}) // skip query/request network if id is null

Answer 1

You can use the @skip or @include directive. If the query ends up being empty following the directive conditions, no network request will be made. Consider the example:

import { useLazyLoadQuery } from 'react-relay/hooks';

function MaybeUser(props) {
  const { userId } = props;
  //        👆 is optional/nullable

  useLazyLoadQuery(
    graphql`
      query MaybeUserQuery($userId: ID!, $skip: Boolean!) {
        user(id: $userId) @skip(if: $skip) {
          fullName
        }
      }
    `,
    {
      userId: userId || '', // we need to pass something because of the query $userId type decleration
      skip: !userId,        // skip when there is no user ID
    },
  );

  return <magic />;
}

Empty userId produces an empty MaybeUserQuery resulting in no network requests.