Key tips:

noEmit: true means that the TypeScript compiler does not generate any output JavaScript (.js) files. This option is typically used when another tool (like Angular CLI or Vite) is responsible for the final JavaScript bundling.

Allow .ts imports (allowImportingTsExtensions: true) relates to how TypeScript resolves modules during compilation, not to JavaScript emitting.

Standard approach (and why noEmit: true is typically paired with this option in modern Angular projects):

In modern Angular development workflows using a bundling tool like Angular CLI or Vite, the TypeScript compiler's primary role is type checking and analysis, not final JavaScript generation. The bundling tool takes the TypeScript code (and other resources) and produces browser-optimized bundles.