tsconfig.json should default `maxNodeModuleJsDepth` to 1

[speigg]

TypeScript Version: 2.4.1

Expected behavior:

Basically, I expected --allowJS to know about modules in node_modules that don't have typescript definitions, the same way that a jsConfig.json project does.

Actual behavior:

Typescript doesn't know about modules in node_modules until the maxNodeModuleJsDepth compiler option is set to 1 or greater. It seems that it used to default to 2, but this was changed to 0 in #10538 (for performance reasons I think?). Given that jsConfig.json defaults this value to 2, can tsConfig.json at least default to 1 so that the --allowJS option works with top-level node modules out of the box?

[mhegazy]

This is an intentional behavior, the information the compiler can pick up from a .js file is less than that from a .d.ts file. Users would get better experience in general if they used @types or wrote a .d.ts file for the library. the feature is still there, and you are more than welcome to set it to 1 or more if you so chose, but we do not believe this should be the default.

[mhegazy]

Automatically closing this issue for housekeeping purposes. The issue labels indicate that it is unactionable at the moment or has already been addressed.