API: make 'isExternalOrCommonJsModule' public

Suggestion

🔍 Search Terms

isExternalOrCommonJsModule, commonJsModuleIndicator

✅ Viability 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, new syntax sugar for JS, etc.)
• This feature would agree with the rest of TypeScript's Design Goals.

⭐ Suggestion

Make the existing utility function ts.isExternalOrCommonJsModule public by moving it from utilities.ts to utilitiesPublic.ts

📃 Motivating Example

TypeScript treats commonJS modules similar to external modules. But currently there's no way for an API user to know whether TypeScript considers a file as commonJS module. SourceFile#commonJsModuleIndicator is not exposed in the public API and there's no ts.isCommonJsModule as pendant to ts.isExternalModule.

💻 Use Cases

My current use case is to determine whether a file (or top-level declaration inside of it) contributes to the global scope. Currently I can only handle external modules, which doesn't match what TypeScript does internally.

Start by reading isExternalOrCommonJsModule in utilities.ts and the public exports in utilitiesPublic.ts. Check how related public utilities such as isExternalModule are exposed and run the relevant compiler API tests; done means the utility is publicly available without changing existing runtime behavior.