SetHeader.js

import { ApolloLink, Observable } from "@apollo/client";

const request = async (operation) => {
    const token = "yourToken"; // you can get token from persistent storage or redux store
    console.log('REQUESTING', operation.operationName, operation.variables);
    operation.setContext({
        headers: {
            authorization: `Bearer ${token}`,
        },
    });
};

const requestLink = new ApolloLink((operation, forward) => new Observable(observer => {
    let handle // ref variable to unsubscribe on dispose
    Promise.resolve(operation)
        .then(opr => request(opr))
        .then(() => {
            handle = forward(operation).subscribe({
                next: observer.next.bind(observer),
                error: observer.error.bind(observer),
                complete: observer.complete.bind(observer)
            })
        })
        .catch(observer.error.bind(observer))
    return () => {
        if (handle) {
            handle.unsubscribe()
        }
    }
}))