AllowJS files in tsserver when no project is given

[billti]

This is a hot issue for VSCode. Effectively, with no config file provided, we don't resolve CommonJS modules in JavaScript files.

The issue is that although allowNonTsExtensions is set by default, allowJs currently isn't, and when nodeModuleNameResolver is called, it only resolves files with supportedExtensions. If allowJs isn't set, then .js isn't in the set of file extensions it looks for.

This is a one line change in tsserver only, so should not impact VS. (We should decide if getDefaultCompilerOptions in services.ts should set this by default also, but this is the minimal/least risk change for now).

[RyanCavanaugh]

👍

[mhegazy]

👍

[egamma]

thanks much!