debian-mirror-gitlab/spec/frontend/__helpers__/test_apollo_link.js

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2022-04-04 11:22:00 +05:30
import { InMemoryCache, ApolloClient, ApolloLink, gql } from '@apollo/client/core';
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const FOO_QUERY = gql`
query {
foo
}
`;
/**
* This function returns a promise that resolves to the final operation after
* running an ApolloClient query with the given ApolloLink
*
* @typedef {Object} TestApolloLinkOptions
* @property {Object} context the default context object sent along the ApolloLink chain
*
* @param {ApolloLink} subjectLink the ApolloLink which is under test
* @param {TestApolloLinkOptions} options contains options to send a long with the query
*
* @returns Promise resolving to the resulting operation after running the subjectLink
*/
export const testApolloLink = (subjectLink, options = {}) =>
new Promise((resolve) => {
const { context = {} } = options;
// Use the terminating link to capture the final operation and resolve with this.
const terminatingLink = new ApolloLink((operation) => {
resolve(operation);
return null;
});
const client = new ApolloClient({
link: ApolloLink.from([subjectLink, terminatingLink]),
// cache is a required option
cache: new InMemoryCache(),
});
// Trigger a query so the ApolloLink chain will be executed.
client.query({
context,
query: FOO_QUERY,
});
});