fix: allow to push single items in arrays

[Yarmeli]

Implemented a fix for #181

[arthurfiorette]

Can you add some tests?

[Yarmeli]

I added some tests, let me know your thoughts on them 😄

Also, I noticed that some tests that should fail, don't really fail, for example:

// literal.test-d.ts

expectAssignable<Model>({
  id: 0,
  simple: 1,
  optional: 2,
  list: [3]
}); // ✅ it passes correctly

// copy the above code and replace the method with 'expectNotAssignable'
expectNotAssignable<Model>({
  id: 0,
  simple: 1,
  optional: 2,
  list: [3]
}); // ❌ the test passes but it should fail because this can be assigned to Model

My understanding is that this happens because of how arrays are handled in the tsd package. I opened an issue in there

[arthurfiorette]

Should I wait for this fix at tsd?

[Yarmeli]

I don't think it would make much of a difference waiting for the tsd fix/suggestion on how to handle arrays since that currently affects new and old tests.

I can open a new issue to improve the tests depending on what the fix is for that issue

[arthurfiorette]

@Yarmeli ok. CI is still failing

[arthurfiorette]

Can you run pnpm prettier --write . and commit the changes

[Yarmeli]

Hopefully, this should have worked 🤞

I am having issues on my local machine with prettier not being able to find prettier plugin modules for this repo 😞

[mrazauskas]

@Yarmeli Just a quick note. Might be you saw already, last week I released TSTyche, a fresh type testing tool. This is the one I promised in tsdjs/tsd#199

Repo: https://github.com/tstyche/tstyche
Documentation: https://tstyche.org

---

Before we talked about widening of inferred types. I explained it in documentation. This is how TypeScript works and that is for good reason. But with TSTyche you can avoid widening in your type tests by comparing two types:

import { expect } from "tstyche";

interface Options {
  locale?: Array<"en" | "de">;
  root?: string;
}

expect<Options>().type.toBeAssignable<{
  locale: ["en", "de"];
}>();

expect<Options>().type.toBeAssignable<{
  root: string;
}>();

Also with TSTyche you can test types on specific versions of TypeScript: tstyche --target 4.8,5.0,latest. Very useful for complex generic types. Give it a try (;

---

PS Commenting here, because I don’t feel like this is anyhow related with tsd.