Document usage of server creation in typescript

Apollo server doesn’t provide any documentation for usage with TypeScript, whilst this wouldn’t normally be an issue for most projects the server uses some advanced types which aren’t obvious to consume.

Example

const server = new ApolloServer({
  typeDefs,
  resolvers,
  dataSources: (): **???** => {
    return {
      blogPostApi: new BlogPostApi(
        config.prismic.url,
        config.prismic.accessToken
      )
    };
  }
});

First pass this looks like it should be DataSource<IDataSources> where IDataSource is something like;

interface IDataSources {
  blogPostApi: IBlogPostApi;
}

But returns;

src/index.ts:47:7 - error TS2322: Type '{ blogPostApi: BlogPostApi; }' is not assignable to type 'DataSource<IDataSources>'.
  Object literal may only specify known properties, and 'blogPostApi' does not exist in type 'DataSource<IDataSources>'.

[lookfirst]

import {DataSource} from "apollo-datasource";
export class MyDataSource extends DataSource {
    // constructor receives the base data source
}

// this is a fugly import imho...
import {DataSources} from "apollo-server-core/dist/graphqlOptions";

export interface IDataSources {
	myDS: MyDataSource;
}

export function buildDataSources() {
	return {
		myDS: new MyDataSource(),
	} as DataSources<IDataSources>;
}

new ApolloServer({
	dataSources: () => buildDataSources(),
})

Not shown here, but I pass the base datasource into buildDataSources() and then through to the MyDataSource wrapper object.

[glasser]

The Apollo Server 4 docs use TypeScript by default (and also let you see code examples as JavaScript).

I agree with you that using dataSources was strange from a typing perspective (for example, it meant that the type of the context value returned from your context function didn’t match the type of the context value available to resolvers and plugins); the dataSources option has been removed from Apollo Server 4 primarily for this reason.