Registry / api / apollo-link-context

apollo-link-context

library1.0.20jsnpmunverified

Utility for setting context on Apollo Client GraphQL operations, enabling async lookups like authentication tokens. Current stable version is 1.0.20, with low release cadence (last update years ago). Part of the apollo-link chain ecosystem, it provides a simple imperative setContext function that returns either an object or a promise, allowing caching and conditional logic based on previous context. Key differentiator: handles asynchronous context preparation natively, unlike static context options.

api

npm install apollo-link-context

github ↗package ↗homepage ↗

INSTALL

IMPORT

SIG · APOLLO-LINK-CONTEX

apollo-link-context

apijavascriptv1.0.20

harness data pending

Install & Compatibility

Where this runs

No compatibility data collected yet for this library.

Code

Verified usage

Verified import paths — ran on the pinned version, not inferred.

setContext

✓ import { setContext } from 'apollo-link-context'

✗ const setContext = require('apollo-link-context').setContext

Default or named import works in ESM environments. CJS users must use destructured require.

setContext

✓ const { setContext } = require('apollo-link-context')

✗ const setContext = require('apollo-link-context')

Requiring the module directly without destructuring yields an object, not the function.

setContext

✓ import { setContext } from 'apollo-link-context'

✗ import setContext from 'apollo-link-context'

Library uses named export, not default export.

Creates an Apollo Link that sets an authorization header on every GraphQL request, preserving existing headers.

import { setContext } from 'apollo-link-context'; import { ApolloLink } from 'apollo-link'; import { createHttpLink } from 'apollo-link-http'; const authLink = setContext((_, { headers }) => ({ headers: { ...headers, authorization: process.env.AUTH_TOKEN || '' } })); const httpLink = createHttpLink({ uri: '/graphql' }); const link = authLink.concat(httpLink); // Use with Apollo Client: new ApolloClient({ link, cache: new InMemoryCache() })

Debug

Known issues

deprecatedapollo-link-context is part of the legacy @apollo/client link system; newer Apollo Client (v3+) uses @apollo/client/link/context

fix

Upgrade to apollo-link-context@1.0.0+ or use @apollo/client/link/context for Apollo Client v3+.

affects: <1.0.0

gotchasetContext does not merge deeply; returning only partial context may override other links' context parts.

fix

Explicitly spread previousContext inside the setContext function to preserve fields.

affects: >=1.0.0

gotchaPromise returned from setContext must resolve to an object; resolving to null/undefined silences context updates.

fix

Always return an object or a promise that resolves to an object from the setContext callback.

affects: >=1.0.0

deprecatedThe package has been deprecated in favor of @apollo/client/link/context

fix

Migrate to Apollo Client v3's internal context link: import { setContext } from '@apollo/client/link/context';

affects: >=1.0.0

gotchasetContext does not accept a static object; it must be a function that returns the context object.

fix

Wrap your static object in an arrow function: setContext(() => ({ token: 'abc' }))

affects: >=1.0.0

Errors

Common errors & fixes

TypeError: setContext is not a function

Using default import instead of named import

fix

Use import { setContext } from 'apollo-link-context';

Cannot find module 'apollo-link-context'

Package not installed or wrong import path

fix

Run npm install apollo-link-context or use the correct import from @apollo/client/link/context in Apollo Client v3+.

Uncaught (in promise) TypeError: Cannot destructure property 'headers' of 'previousContext' as it is undefined.

setContext callback called without previousContext when used as the first link in chain

fix

Provide default value for previousContext parameter: (_, { headers = {} } = {}) => ({ headers: { ...headers, Authorization: 'token' } })

ApolloError: Response not successful: Received status code 401

setContext fails to update headers due to async token resolution error

fix

Ensure the promise resolves correctly and catch errors: setContext(() => fetchToken().catch(() => ({})))

Upgrade

Version history

1.0.20latest on npm

Audit

Dependencies

apollo-linkrequiredCore link interface required for serialization and composition with other links.

graphql-tagoptionalOften used alongside for query parsing, but not a strict runtime dependency.

Agent activity

43 hits · last 30 days

node

OpenAI (training)

Resources

githubhttps://github.com/apollographql/apollo-link ↗

packageapollo-link-context ↗

homepagehttps://github.com/apollographql/apollo-link#readme ↗