MaxAge ApolloLink

Purpose

An Apollo Link to invalidate cached queries.

Installation

yarn add apollo-link-maxage
npm install --save apollo-link-maxage

Usage

Simply specify maxAge in a query's context. This could be a number of ms or a string (i.e. 10s for 10 seconds, 5m for 5 minutes etc.).

import { MaxAgeLink } from 'apollo-link-maxage';
import { InMemoryCache } from 'apollo-inmemory-cache';

const myCache = new InMemoryCache();
const maxAgeLink = new MaxAgeLink({
  cache: myCache,
});

// query options
{
  query: gql`
    query me {
      me {
        name
      }
    }
  `,
  fetchPolicy: 'network-only',
  context: {
    maxAge: '5m', // or 300000 (5m in ms)
  },
}

NOTE: It's important to set fetchPolicy to network-only or similar. This is because ApolloClient won't execute a Link if there is no need to fetch a result from a GraphQL endpoint.

How it works

If a query runs for a first time, it's being executed normally but the expiration date is stored. Next time it runs the MaxAgeLink checks if a query is expired, if not it reads results from cache, otherwise the process starts again.

To match a query with the one that has been stored we need to generate a unique key. By default it uses ApolloLink's toKey() method but you can define your own logic by providing a function as toKey option.

Options

• cache - instance of ApolloCache (required)
• toKey - a function that receives an Operation and returns a unique string ((op: Operation) => string)