feat(typescript): detect typescript based on tsconfig.json

[pi0]

• Refactor registerTSNode from @nuxt/typescript into @nuxt-cli. This way users can keep @nuxt-typescript (~55.2 MB) into devDependencies and ts-node (1.6 MB) in dependencies. This means much less production install size and also have runtime support.
• Move external imports into cli/imports.js for better maintenance.
• Only enable typescript for a project if tsconfig.json exists in the rootDir.
• Only If tsconfig.json is empty JSON, defaults will be written into it by @nuxt/typescript.

[manniL]

We have to highlight that change in the release notes (as done before with changes on experimental features) ☺️

[pi0]

@manniL Sure. Actually it is a complement of #5367. New migration guide would be:

1. Remove nuxt-ts dependency
2. Add nuxt and ts-node to dependencies:
   • yarn: yarn add nuxt ts-node
   • npm: npm i nuxt ts-node
3. Add @nuxt/typescript to devDependencies:
   • yarn: yarn add -D @nuxt/typescript
   • npm: npm i @nuxt/typescript
4. Create an empty tsconfig.json file. Nuxt will automatically generate it with defaults at first run, then you can edit it to fit your needs.

Nuxt 2.5 users may only require to add ts-node to the dependencies

[kevinmarrec]

Wow, nice work @pi0 !!!

So I guess we can close nuxt/docs#1269 (which was linked to #5367 ) and start from current docs https://nuxtjs.org/guide/typescript to just add the ts-node thing ?

[kevinmarrec]

Migration guide for 2.5.x projects should be just installing ts-node as dependency if they need runtime support.

[kevinmarrec]

@pi0 ts-node shouldn't be removed from packages/typescript/package.json then ?

[pi0]

@kevinmarrec Migration guide updated. Does it looks good now? (Feel free editing my comment).

@pi0 ts-node shouldn't be removed from package.json then ?

For lazy people who only install @nuxt/typescript that would be harmless. But can be removed as well.

[kevinmarrec]

@pi0 perfect

Yeah I see, but if it's not used anymore within this package, we probably should remove it ?
It would indeed mean we need to warn users in release notes they need to install ts-node back when migrating to 2.6 (if they're using nuxt.config.ts or any thing that need runtime support)

[pi0]

@kevinmarrec Done. Dependency removed and guide updated. I had to add ts-node to nuxt mono-repo root package.json in order to CI passing

[kevinmarrec]

Alright perfect @pi0, worth mentionning that the guide is applicable for 2.4.x -> 2.6.x.
For 2.5.x -> 2.6.x it's only the ts-node step.

Don't know how exactly we're gonna wrap it up in release notes but yeah 🙈

[codecov-io]

Codecov Report

Merging #5412 into dev will increase coverage by <.01%.
The diff coverage is 90%.

@@            Coverage Diff             @@
##              dev    #5412      +/-   ##
==========================================
+ Coverage   96.17%   96.17%   +<.01%     
==========================================
  Files          74       74              
  Lines        2534     2539       +5     
  Branches      644      646       +2     
==========================================
+ Hits         2437     2442       +5     
  Misses         81       81              
  Partials       16       16

Impacted Files	Coverage Δ
packages/cli/src/command.js	98.97% <100%> (ø)	⬆️
packages/typescript/src/index.js	100% <100%> (ø)	⬆️
packages/cli/src/imports.js	100% <100%> (ø)	⬆️
packages/cli/src/utils/typescript.js	85.71% <83.33%> (+19.04%)	⬆️
packages/vue-renderer/src/renderer.js	95.52% <0%> (-0.5%)	⬇️

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