Using NodeJS builtins

I was extremely pleased to see my TS compile to perfect -O ADVANCED output after adding the tsconfig.json, but when I add a simple builtin import:

import { exec } from 'child_process';

I receive the following error:

TSCC: tsickle converts TypeScript modules to Closure modules via CommonJS internally."module" flag is overridden to "commonjs".
TSCC: tsickle uses a custom tslib optimized for closure compiler. importHelpers flag is set.
TSCC: Module name child_process was not provided as a closure compilation source
TSCC: The compilation has terminated with an error.

This is one of the larger pains with Closure Compiler in general - Node builtins should be automatically detected (opt-out with a flag) and supplied as externs, and left untouched in output. TSCC does a fantastic job of handling thousands of other problems, but if we can’t compile programs containing Node builtins, we can’t realize the full benefit.

Any thoughts on this or recommendations? The test program is below.

import path from 'path';
console.log(path.resolve('.'));

[theseanl]

I suppose you can do something like this:

{
	"external": {
		"path": "path"
	},
	"compilerFlags": {
		"output_wrapper": "(function(path){%output%})(require('path'))"
	}
}

[theseanl]

As far as I know, tsickle does not support esModuleInterop flag. tslib.__importDefault is generated by this flag, so if you remove the esModuleInterop flag, it will compile well, I guess. I am not sure what --dependency_mode PRUNE_LEGACY exactly does, but the compilation should not fail without adding any additional flags to the closure compiler.

Most of time, you can replace default imports to namespace imports (import * as ns from '...') and the runtime behavior will be the same.

It’d be better to have esModuleInterop supported, but IMO a better place for the support would be from tsickle, not from here, that’s why I am not currently working on it.