Middleware for the apollo client's network interface

middleware.js

import { ApolloClient } from "apollo-client"
import { createNetworkInterface } from "apollo-client/lib/src/networkInterface"


// Middleware functions can perform the following tasks:
//
// -  Execute any code.
// -  Make changes to the request and request option objects.
// -  Call the next middleware function in the stack.
//
// modeled after express 4.0

const heighliner = createNetworkInterface('http://localhost:8888/');

interface MiddlewareRequest {
  request: Request;
  options: RequestInit;
}

// option 1, generic middleware that can modify the options of the request
const tokenMiddleware = (request: MiddlewareRequest, next: function): void => {
  // this would be called on each request and has the option to modify the headers
  // this doesn't return a value, but rather modifies the request inline.
  // that feels gross but I don't know of another way to do next() unless you pass
  // the request into next? which also seems odd
};

// option 2, authorization sugaring of option 1 that only modifies the headers
// and defaults to setting an 'Authorization' header.
heighliner.authorize('token': string, /* optional key name for token : string*/);
heighliner.removeAuthorization(/* probably just a null value here? */);


// the middleware would be on the networkInterface itself
// should this be an array? or allow for multiple arugments to be passed as args
// e.g. `use(middleware1, middleware2, etc)
heighliner.use(tokenMiddleware);

const apolloClient = new ApolloClient({
  networkInterface: heighliner,
  apolloStore: apolloStore
});

// if the default networkInterface is used, you can do soemthing like this
const client = new ApolloClient();
const { networkInterface } = client;
networkInterface.use(/* middleware */);
networkInterface.authorize('token', /* optional key name for token */);