feat: type Fastify context properly

[SimenB]

This way a context function provided to new ApolloServer is typed correctly.

I copied this approach from the Express plugin:

apollo-server/packages/apollo-server-express/src/ApolloServer.ts

Lines 37 to 56 in 48d3ab2

	export interface ExpressContext {
	req: express.Request;
	res: express.Response;
	}
	export type ApolloServerExpressConfig = Config<ExpressContext>;
	export class ApolloServer<
	ContextFunctionParams = ExpressContext,
	> extends ApolloServerBase<ContextFunctionParams> {
	// This translates the arguments from the middleware into graphQL options It
	// provides typings for the integration specific behavior, ideally this would
	// be propagated with a generic to the super class
	async createGraphQLServerOptions(
	req: express.Request,
	res: express.Response,
	): Promise<GraphQLOptions> {
	const contextParams: ExpressContext = { req, res };
	return super.graphQLServerOptions(contextParams);
	}

[SimenB]

they're not actually optional:

apollo-server/packages/apollo-server-fastify/src/ApolloServer.ts

Line 113 in 48d3ab2

this.createGraphQLServerOptions(request, reply),

[SimenB]

already typed

[glasser]

This looks good. It should get a CHANGELOG.md entry mentioning the new type exports; we'll merge it once that is added, or will write it ourselves eventually.

[SimenB]

Thanks @glasser!