Not only VSCode, it's a documented feature of the ts compiler. https://www.typescriptlang.org/docs/handbook/type-checking-javascript-files.html https://www.type

Not only VSCode, it's a documented feature of the ts compiler. https://www.typescriptlang.org/docs/handbook/type-checking-javascript-files.html https://www.typescriptlang.org/docs/handbook/type-checking-j... iirc Webpack uses it extensively in its codebase