Suggestion: support Node `require` in ES Modules

Search Terms

node require commonjs webpack conditional dynamic import

Suggestion

Node style require’s are often used inside ES Modules for conditional imports. For example:

const getSentry = () => {
  if (__CLIENT__) {
    return require('./client-sentry').default;
  } else {
    return require('./server-sentry').default;
  }
};

export default getSentry();

In this example, require returns any as per the typings provide by @types/node.

https://github.com/DefinitelyTyped/DefinitelyTyped/blob/5f59f3dc7a0965fb1767cf13c670c633bbbbf0a8/types/node/globals.d.ts#L190-L193

In order to acquire types, we have to use import types:

type ClientSentry = typeof import('./client-sentry');
type ServerSentry = typeof import('./server-sentry');

const getSentry = () => {
  if (__CLIENT__) {
    return (require('./client-sentry') as ClientSentry).default;
  } else {
    return (require('./server-sentry') as ServerSentry).default;
  }
};

export default getSentry();

I would like to suggest that TypeScript supports require calls inside of ES Modules (in Node envs). This way the workaround would not be necessary. Alternatively, perhaps TypeScript could make it possible for @types/node to improve the return type of require, e.g.

interface NodeRequireFunction {
    <Id extends string>(id: Id): typeof import(Id);
}

Note that require is desirable over dynamic imports because it is synchronous.

Checklist

My suggestion meets these guidelines:

• This wouldn’t be a breaking change in existing TypeScript/JavaScript code
• This wouldn’t change the runtime behavior of existing JavaScript code
• This could be implemented without emitting different JS based on the types of the expressions
• This isn’t a runtime feature (e.g. library functionality, non-ECMAScript syntax with JavaScript output, etc.)
• This feature would agree with the rest of TypeScript’s Design Goals.

[andrewbranch]

Note that in #44501, the TS import Foo = require("...") will be desugared to a createRequire’d require call.

[Lemmingh]

The example above seems not complete.

require() does not exist in ES module on Node.js since draft. It needs to be constructed with helpers:

import { createRequire } from "module";
const require = createRequire(import.meta.url);

Then, I guess changing @types/node type definitions won’t help, but TypeScript needs to resolve semantics for module.createRequire().