Consider changing rules for determining whether a project uses TS

[tgriesser]

What would you like?

From #22004

I don’t have a tsconfig, don’t use typescript in the project, I have a tsconfig.json.ignore from back when I did, but that’s clearly nothing

We should probably tighten the algorithm for determining whether to use ts or not in a project from:

IF `typescript` dependency in `package.json` OR `tsconfig.json` in `projectRoot/*`

to:

IF `typescript` dependency in `package.json` AND `tsconfig.json` in `projectRoot/*`

We should be detecting via existence in dependencies / devDependencies / peerDependencies as well as resolving it to confirm it's usable

cc @ZachJW34 / @lmiller1990 as I think y'all worked on this one the most.

Why is this needed?

No response

Other

Related: #21927

[jennifer-shehane]

Let's make sure to update the tech-brief if we change this logic.

[lmiller1990]

We should be detecting via existence in dependencies / devDependencies / peerDependencies rather than resolving it

I don't think we are resolving it anywhere during detection. What gave you this impression?

We can easily make the suggested change. I don't think it'll solve any existing problems, though - tsconfig.json.ignore won't be detected by our glob:

cypress/packages/scaffold-config/src/detect.ts

Line 134 in 369a865

joinPosix('**/*tsconfig.json'),

I think there are some outstanding issues in #22004 that are not related to the TS detection algorithm.

[lmiller1990]

Also @tgriesser I wonder if we want to rethink the brief a little as part of this. I made a PR: https://github.com/cypress-io/tech-briefs/pull/28. What do you think?

[tgriesser]

Yeah, let's make this change - seems it's a common enough issue that folks are running into

[tgriesser]

Actually, we probably should also be resolving it, because if they don't have it installed it'll immediately error for them when they scaffold

[cypress-bot]

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