Support ES modules

import { ApolloServer } from 'apollo-server'

does not work in Node 13 with "type": "module" in package.json. More info here: https://github.com/apollographql/apollo-server/issues/1356#issuecomment-567101161

import { ApolloServer } from 'apollo-server'
         ^^^^^^^^^^^^
SyntaxError: The requested module 'apollo-server' does not provide an export named 'ApolloServer'
    at ModuleJob._instantiate (internal/modules/esm/module_job.js:92:21)
    at async ModuleJob.run (internal/modules/esm/module_job.js:107:20)
    at async Loader.import (internal/modules/esm/loader.js:164:24)

[derekjwilliams]

The workaround that I found (from https://github.com/apollographql/apollo-server/issues/1356) is

import apollo from 'apollo-server'
const { ApolloServer } = apollo

[glasser]

Hmm. While we didn’t actually do any particular work to make ESM work, I agree with @trevorblades that it does seem to work, at least with Node 14!

The comments from @lorensr and @derekjwilliams predate Node 14.

@platocrat 's comment first is about what happens when you lack "type": "module", and then is about a require in their own code, not in Apollo Server.

This comment references an error message that this comment suggests is resolved in Node v14.13 (and v12.20). (I think this PR is the relevant one.)

This comment from @jaibatrik and this comment from @mushketyk don’t have enough information to reproduce.

I’m going to assume that this issue is now fixed, as long as you’re on Node v14.13 or v12.20! If anyone (esp @jaibatrik or @mushketyk) can demonstrate ESM imports not working with one of those versions of Node (perhaps start by forking @trevorblades 's sandbox above) then we can reopen it.

(Separately, it might be nice to publish apollo-server built as ESM itself, but I don’t know if that actually helps with any specific use cases. For Apollo Client we’re doing that so you can load directly from a site like esm.run, but that seems less relevant for a server project.)