TypeScript: Type inference question with TS v4.2

[oscard0m]

Hi all,

I tried to find out a conversation we had in a couple of issues/pull requests in octokit lately regarding Webhooks typing inference. What I found is these comments:

• fix(types): add explicit return type to webhooks() function app.js#201 (comment)
• fix(types): add explicit return type to webhooks() function app.js#201 (comment)

Do you think this new improvement in TS 4.2 could help in Octokit type inference problem with Webhooks?

Here I would like some TS expertise from @wolfy1339 and @G-Rath

[gr2m]

Very cool! I'm excited to see how this change impacts types for @octokit/* modules!

You could try reverting octokit/app.js#201 and installing TypeScript 4.2 locally, then see what type is shown in VS Code?

[oscard0m]

@wolfy1339 Could you try running tsc on it? Checking the issue seems to be happening when running tsc.

[wolfy1339]

Running tsc doesn't seem to do anything to fix it. It just transpiles the TS source into JS and doesn't do anything with the type information

[oscard0m]

This is the full command reported in the issue, maybe you need to run the full command?

node_modules/typescript/bin/tsc --outDir pkg/dist-src/ -d --declarationDir pkg/dist-types/ --project tsconfig.json --target es2020 --module esnext --noEmit false --sourceMap false src/webhooks.ts:8:17

Check run with details here: https://github.com/octokit/app.js/runs/1858152718?check_suite_focus=true#step:5:14

npm run build in the project or pika build downgrading the commit and trying TS4.2 vs TS4.1?

[wolfy1339]

That's exactly the process I followed when I tested

[oscard0m]

Strange. What we could do is, first make sure TS4.2 is used everywhere it Octokit and, from there opening a PR 'reverting' this types and with Pika's generated package play with it and see if we are able to reproduce the error again.

[G-Rath]

4.2 has actually been released a few hours ago, so we can upgrade and see what happens.