#ESM

New #ESM features are coming to TypeScript:
https://devblogs.microsoft.com/typescript/announcing-typescript-4-7-beta/

And what about our beloved package-lock.json? It guarantees that all
dependencies and sub-dependencies are installed with a specific version, which
ensures that everyone building and executing the code gets a specific state (see
@ReproBuilds). #ESM only pins the top-level.

Looking a little bit into the future of browser apps which will no longer use
pre-compiled code using e.g. #webpack, but fetch dependencies using #esm
(ECMAScript module): we need to shift testing environments to actually use
browsers (albeit headless) as the test runner.