How to find/debug what file(s) included given file during typescript compilation

Search Terms

find why was file included during typescript build

Suggestion

Be able to find out why a file was checked by TS compiler during a build.

Use Cases

Sometimes testing files gets somehow mixed into the type checking for dev/prod builds.

Examples

If a flag explain-inclusion=FLFolder.mock.ts is present:

projects/folder-listing/src/app/services/FLEntities/FLFolder.mock.ts was included, because it was requested by:

• projects/folder-listing/src/app/services/FLEntities/FLFolder.ts at (3:26)
• projects/folder-listing/src/app/services/main.service.ts (7:10)
  ... (Only first level, the developer should repeat the process as needed)

Checklist

My suggestion meets these guidelines:

• This wouldn't be a breaking change in existing TypeScript/JavaScript code
• This wouldn't change the runtime behavior of existing JavaScript code
• This could be implemented without emitting different JS based on the types of the expressions
• This isn't a runtime feature (e.g. library functionality, non-ECMAScript syntax with JavaScript output, etc.)
• This feature would agree with the rest of TypeScript's Design Goals.

The issue does not name implementation files, tests, or compiler entry points. Start by tracing how TypeScript determines file inclusion and how existing command-line diagnostics are exposed. Done means a documented or tested way to identify why a file was included, including the requesting file and source location described in the example.