@urql/exchange-persisted#

The persistedExchange is an exchange that allows other terminating exchanges to support Persisted Queries, and is as such placed in front of either the default fetchExchange or other terminating exchanges.

Quick Start Guide#

First install @urql/exchange-persisted alongside urql:

yarn add @urql/exchange-persisted
# or
npm install --save @urql/exchange-persisted

You'll then need to add the persistedExchange function, that this package exposes, to your exchanges.

import { createClient, fetchExchange, cacheExchange } from 'urql';
import { persistedExchange } from '@urql/exchange-persisted';

const client = createClient({
  url: 'http://localhost:1234/graphql',
  exchanges: [
    cacheExchange,
    persistedExchange({
      /* optional config */
    }),
    fetchExchange,
  ],
});

The persistedExchange supports three configuration options:

• preferGetForPersistedQueries: Enforce GET method to be used by the default fetchExchange for persisted queries
• enforcePersistedQueries: This disables automatic persisted queries and disables any retry logic for how the API responds to persisted queries. Instead it's assumed that they'll always succeed.
• generateHash: A function that takes a GraphQL query and returns the hashed result. This defaults to the window.crypto API in the browser and the crypto module in Node.
• enableForMutation: By default, the exchange only handles query operations, but enabling this allows it to handle mutations as well.

Avoid hashing during runtime#

If you want to generate hashes at build-time you can use a webpack-loader to achieve this, when using this all you need to do in this exchange is the following:

import { createClient, fetchExchange, cacheExchange } from 'urql';
import { persistedExchange } from '@urql/exchange-persisted';

const client = createClient({
  url: 'http://localhost:1234/graphql',
  exchanges: [
    cacheExchange,
    persistedExchange({
      generateHash: (_, document) => document.documentId,
    }),
    fetchExchange,
  ],
});