TypeScript 4.5 Beta Exports

Run npm install on top-level to install and build all packages.

To test auto import make sure to use the workspace version of TypeScript in VSCode.

You may also want to start a clean version of VSCode via code --extensions-dir /tmp/code-ext --user-data-dir /tmp/code-profile .

Packages

• importer – Playground to test auto import (e.g. in main.js)
• exporter-old – Uses the "old" types field in package.json
• expoter – Uses the new exports field to expose root module and a feature module
• exporer-all – Uses the new exports but exposes everything via ./*

Problem 1 – Auto import doesn't work as expected

// Works: auto-import ExportMainFunction (this didn't work in an earlier repro, but now it does; not sure why.)
// Works: auto-import ExportOldMainFunction

// Doesn't work: auto-import ExportFeature (it does work when something from "exporter/feature" was exported elsewhere)
// Doesn't work: auto-import ExportAllMain (cannot even be imported manually)

Manually importing them and running node main.js works without any problems, so the exports should be correct at least by Node.js's logic.

Also, it seems like in the exporter package, one has has to specify types in addition to module. I would expect this not to be necessary when the declaration file is located next to the JS file.

Problem 2 – Watch mode behaves strangely

There is also different, probably unrelated problem with tsc -w. The initial build of tsc -w in the importer package generated the correct code for main.ts, a subsequent build generates the code with the wrong target (looks like ES5?), yet another build (and apparently all builds that follow) again generates the correct code.

To reproduce, run npx tsc -w in the importer package, look at lib/main.js and then trigger a change in src/main.ts; the lib/main.js will contain code generated for the wrong target. src/main.ts should contain some code to actually see the problem.