useMutation

useMutation

Hook used to execute a mutation in a React component.

import type {FeedbackLikeMutation} from 'FeedbackLikeMutation.graphql';
const React = require('React');

const {graphql, useMutation} = require('react-relay');

function LikeButton() {
  const [commit, isInFlight] = useMutation<FeedbackLikeMutation>(graphql`
    mutation FeedbackLikeMutation($input: FeedbackLikeData!) {
      feedback_like(data: $input) {
        feedback {
          id
          viewer_does_like
          like_count
        }
      }
    }
  `);

  if (isInFlight) {
    return <Spinner />;
  }

  return (
    <button
      onClick={() => {
        commit({
          variables: {
            input: {
              id: '123',
              text: 'text',
            },
          },
          onCompleted(data) {
            console.log(data);
          },
        });
      }}
    />
  );
}

Arguments

• mutation: GraphQL mutation specified using a graphql template literal.

• commitMutationFn: <T: MutationParameters>(IEnvironment, MutationConfig<T>): Disposable. [Optional] A function with the same signature as commitMutation, which will be called in its stead. Defaults to commitMutation.

Return Value

Tuple containing the following values:

• [0] commitMutation: The function that will execute the mutation
  • Arguments, the syntax signature is almost the same as our commitMutation API
    • variables: Object containing the variables needed for the mutation. For example, if the mutation defines an $input variable, this object should contain an input key, whose shape must match the shape of the data expected by the mutation as defined by the GraphQL schema.
    • onCompleted: Callback function executed when the request is completed and the in-memory Relay store is updated with the updater function. Takes a response object, which is the "raw" server response. Internally errors are not allowed, CRITICAL error will be thrown in the onError handler.
    • onError: Callback function executed if Relay encounters an error during the request. Internally, CRITICAL error during reading the mutation result on the server
    • optimisticResponse: Object containing the data to optimistically update the local in-memory store, i.e. immediately, before the mutation request has completed. This object must have the same shape as the mutation's response type, as defined by the GraphQL schema. If provided, Relay will use the optimisticResponse data to update the fields on the relevant records in the local data store, before optimisticUpdater is executed. If an error occurs during the mutation request, the optimistic update will be rolled back.
    • optimisticUpdater: Function used to optimistically update the local in-memory store, i.e. immediately, before the mutation request has completed. If an error occurs during the mutation request, the optimistic update will be rolled back. This function takes a store, which is a proxy of the in-memory Relay Store. In this function, the client defines how to update the local data via the store instance. For details on how to use the store, please refer to our Relay Store API Reference. Please note:
      • It is usually preferable to just pass an optimisticResponse option instead of an optimisticUpdater, unless you need to perform updates on the local records that are more complicated than just updating fields (e.g. deleting records or adding items to collections).
      • If you do decide to use an optimisticUpdater, often times it can be the same function as updater.
    • updater: Function used to update the local in-memory store based on the real server response from the mutation. If updater is not provided, by default, Relay will know to automatically update the fields on the records referenced in the mutation response; however, you should pass an updater if you need to make more complicated updates than just updating fields (e.g. deleting records or adding items to collections). When the server response comes back, Relay first reverts any changes introduced by optimisticUpdater or optimisticResponse and will then execute updater. This function takes a store, which is a proxy of the in-memory Relay Store. In this function, the client defines how to update the local data based on the server response via the store instance. For details on how to use the store, please refer to our Relay Store API
    • uploadables: An optional uploadable map, an object representing any number of uploadable items, with one key per item. Each value must be of type File or Blob.
    • No environment argument: useMutation will automatically use the current environment provided by RelayEnvironmentProvider
  • Return value:
    • disposable: Object containing a dispose function. Calling disposable.dispose() will revert the optimistic update, and Relay won't update the store or call any success/error callback, but the network request is not guaranteed to be cancelled. If the dispose is called after the mutation has succeeded, it will not rollback the update in Relay store.
• [1] areMutationsInFlight: Will be true if any mutation triggered by calling commitMutation is still in flight. If you call commitMutation multiple times, there can be multiple mutations in flight at once.

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