Registry / api / apollo-link

apollo-link

library1.2.14jsnpmunverified

Apollo Link is the standard interface for modifying control flow of GraphQL requests and fetching GraphQL results, designed to provide a simple GraphQL client that is capable of extensions. Version 1.2.14 is stable with no active development; consider using @apollo/client (v3+) which includes links natively. Differentiators: composable chain of middleware, Observable-based, supports subscriptions.

api

npm install apollo-link

github ↗package ↗homepage ↗

INSTALL

IMPORT

SIG · APOLLO-LINK

apollo-link

apijavascriptv1.2.14

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.

ApolloLink

✓ import { ApolloLink } from 'apollo-link'

✗ const ApolloLink = require('apollo-link').default

Default export in CJS, named export in ESM; ApolloLink class must be extended.

Observable

✓ import { Observable } from 'apollo-link'

✗ import Observable from 'apollo-link'

Named export, not default. Used for creating custom links.

execute

✓ import { execute } from 'apollo-link'

✗ import { execute } from 'apollo-client'

execute function is part of apollo-link, not apollo-client.

Creates a custom Apollo Link that sends GraphQL requests over HTTP using fetch, demonstrating Observable usage.

import { ApolloLink, Observable } from 'apollo-link'; import { print } from 'graphql/language/printer'; class MyLink extends ApolloLink { request(operation, forward) { if (forward) return forward(operation); return new Observable(observer => { fetch('/graphql', { method: 'POST', headers: { 'Content-Type': 'application/json' }, body: JSON.stringify({ query: print(operation.query), variables: operation.variables }) }) .then(res => res.json()) .then(result => { observer.next(result); observer.complete(); }) .catch(err => observer.error(err)); }); } } const link = new MyLink(); link.request({ query: '{ hello }', variables: {} }).subscribe({ next: console.log, error: console.error });

Debug

Known issues

deprecatedapollo-link is deprecated. Use @apollo/client which includes links natively.

fix

Migrate to @apollo/client and use ApolloClient with ApolloLink from that package.

affects: >=1.0

breakingBreaking change: Inline fragments inside @export directives fail in Apollo Link as of v1.2.4

fix

Upgrade to @apollo/client which handles this correctly.

affects: >=1.2.4 <1.3.0

gotchaCommon mistake: using `require('apollo-link')` returns default export as object with ApolloLink, Observable, etc. Named imports require destructuring.

fix

Use import syntax: import { ApolloLink } from 'apollo-link'

affects: >=1.0

gotchaCommon mistake: `forward` argument may be undefined if link is terminal. Must check before calling forward(operation).

fix

Check if forward exists: if (forward) return forward(operation); else return new Observable(...)

affects: >=1.0

Errors

Common errors & fixes

Uncaught TypeError: forward is not a function

Calling forward(operation) without checking if forward exists in a terminal link.

fix

Check if forward is defined before calling: if (forward) return forward(operation);

Module not found: Can't resolve 'apollo-link'

Package not installed or not in node_modules.

fix

Run: npm install apollo-link graphql

TypeError: Observable is not a constructor

Importing Observable as default instead of named export.

fix

Use: import { Observable } from 'apollo-link'

import { ApolloLink } from 'apollo-link' returns undefined

Using CommonJS require without destructuring in CJS environment.

fix

Use: const { ApolloLink } = require('apollo-link');

Upgrade

Version history

1.2.14latest on npm

Audit

Dependencies

graphqlrequiredpeer dependency for GraphQL types and execution

Agent activity

73 hits · last 30 days

node

OpenAI (training)

Resources

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

packageapollo-link ↗

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