Feature Request: Support for ES Modules

[nickcox]

Afaict, there's no way to use an ES module based hander right now.

It would be awesome to have one less build step. Just wondering if this is on the roadmap?

[jimmywarting]

This code needs to be aware if the package.json has "type": "module" and if it is... then it needs to use dynamic import import(path) instead, this is allowed from node v12.20 and onwards from commonjs

aws-lambda-nodejs-runtime-interface-client/src/utils/UserFunction.ts

Lines 70 to 87 in c31c41f

	/**
	* Attempt to load the user's module.
	* Attempts to directly resolve the module relative to the application root,
	* then falls back to the more general require().
	*/
	function _tryRequire(appRoot: string, moduleRoot: string, module: string): any {
	const lambdaStylePath = path.resolve(appRoot, moduleRoot, module);
	if (_canLoadAsFile(lambdaStylePath)) {
	return require(lambdaStylePath);
	} else {
	// Why not just require(module)?
	// Because require() is relative to __dirname, not process.cwd()
	const nodeStylePath = require.resolve(module, {
	paths: [appRoot, moduleRoot],
	});
	return require(nodeStylePath);
	}
	}

but b/c you use typescript and downlevel everything to commonjs 👎 so it outputs something like __importStar(require('module'))) after you have compiled the source, then you need to use this to prevent typescript from rewriting import to require:

const _importDynamic = new Function('modulePath', 'return import(modulePath)')
_importDynamic(path)

(Imo i think you should ditch typescript, switch to ESM and not transpile anything - but this is just my opinion)

[krk]

This is fixed in #70.