Why does RequestHeaders have the get key?

[aarontravass]

Servers implementing the IncomingHttpHeaders interface result in conflicting types. How can it be resolved?

[enisdenjo]

The Fetch API request headers use the get method while Node's incoming message headers is an object.

There should be no conflicts, can you share an example or a repro?

[aarontravass]

something like this

import { createHandler } from "graphql-http";

const handler = createHandler({
  context: (req) => ({
    auth: req.headers.authorization
  }),
});

Error:

Conflict:

import type { Request } from "@tinyhttp/app";
import {createHandler} from "graphql-http";

const handler = createHandler({
  context: (req: Request) => ({
      auth: req.headers.authorization
    })
  });

[enisdenjo]

graphql-http has its own Request, you cannot override it. You can either:

import { createHandler } from 'graphql-http';

const handler = createHandler({
  context: (req) => ({
    auth:
      typeof req.headers.get === 'function'
        ? req.headers.get('authorization')
        : Object(req.headers).authorization,
  }),
});

or

import { createHandler } from 'graphql-http';
import type { Request } from '@tinyhttp/app';

const handler = createHandler<Request>({
  context: (req) => ({
    auth: req.raw.headers.authorization,
  }),
});

[aarontravass]

But shouldn't RequestHeaders implement the same interface as IncomingHttpHeaders from "http"?

[enisdenjo]

It does implement it.

graphql-http is server agnostic, it can run in any JavaScript environment - both the Fetch API request and Node's http module. So it implements both:

graphql-http/src/handler.ts

Lines 31 to 47 in 91aea45

	/**
	* The incoming request headers the implementing server should provide.
	*
	* @category Server
	*/
	export type RequestHeaders =
	| {
	/**
	* Always an array in Node. Duplicates are added to it.
	* Not necessarily true for other environments.
	*/
	'set-cookie'?: string | string[] | undefined;
	[key: string]: string | string[] | undefined;
	}
	| {
	get: (key: string) => string | null;
	};