tsc with --allowJS ignores modules in node_modules

[speigg]

TypeScript Version: 2.4.1

Code

// A *self-contained* demonstration of the problem follows...
import module = require('module-in-node_modules-with-jsdoc-annotations');

Compiling with commonjs module resolution, and the --allowJS and --checkJS compiler options.

Expected behavior:

1. Typescript should be able to "find" any modules that are installed (e.g. in "node_modules"), even if it doesn't have type definitions for them.
2. Typescript should be able to rely on jsdoc annotations within those modules for type checking and language services.

Actual behavior:

[ts] Cannot find module 'module-in-node_modules-with-jsdoc-annotations'.

[speigg]

I just discovered the maxNodeModuleJsDepth compiler option!

It seems that the default for maxNodeModuleJsDepth is 0?

Setting it to 1 (or greater, obviously) fixes the problem. (Also, it seems I don't need to use the --checkJS to make this work after all).

Anyway, it would be nice if the maxNodeModuleJsDepth were set to 1 by default, so that only the --allowJS is needed for top-level node modules. Closing since I found a solution though.

[speigg]

For reference, looks like maxNodeModuleJsDepth originally defaulted to 2, but this was changed to 0 for performance reasons in #10538