tsConfig option doesn't work

[aantipov]

Version: 4.0.0-beta.2

Problem
Documentation says that I can provide typescript configuration options using

jest.globals['vue-jest'].tsConfig

The problem is that tsConfig option doesn't work and application's root tsconfig.json is always being picked up.

I found that the problem is this code:

const getTsJestConfig = function getTsJestConfig(config) {
  const createTransformer = require('ts-jest').createTransformer
  const tr = createTransformer()
  const { typescript } = tr.configsFor(config)
  return { compilerOptions: typescript.options }
}

The code above relies on ts-jest package to get typescript configuration and passes a whole jest config to it.
ts-jest knows nothing about vue-jest, and thus our jest.globals['vue-jest'].tsConfig is just being ignored.

Proposed solution
To fix the problem I suggest to put tsConfig options under jest.globals['ts-jest']:

const getTsJestConfig = function getTsJestConfig(jestConfig) {
  const createTransformer = require('ts-jest').createTransformer
  const tr = createTransformer()
  const tsConfig = getVueJestConfig(jestConfig).tsConfig;
  const config = Object.assign(
                     {}, 
                     jestConfig || {}, 
                     { globals: {'ts-jest': { tsConfig }}}
                 ); 
  const { typescript } = tr.configsFor(config)
  return { compilerOptions: typescript.options }
}

I can prepare a PR if we agree on the solution

[eddyerburgh]

The documentation is ready yet, but vue-jest 4 uses ts-jest to resolve the ts-config, so you need to use the ts-jest config options.

Let me know how it goes. We're still undecided whether to use ts-jest to resolve, to write and maintain our own, or to rely on babel for compiling TS files.

[aantipov]

vue-jest 4 uses ts-jest to resolve the ts-config, so you need to use the ts-jest config options

Yep, this is exactly what I came to and use this workaround at the moment (specify jest.globals['ts-jest']. tsConfig option).
Still, the documentation is totally misleading and it took me quite a while to figure out what is wrong and how to fix it. I believe it's a bug and we need to fix it ASAP.

To me, the fact that vue-jest relies on ts-jest is an internal thing that we don't need to leak into the documentation. I would rather fix the problem in the code.

In the meantime, we can discuss a question of how to resolve ts configuration and whether we need to rely on babel to compile TS files.

[eddyerburgh]

I disagree that it's a bug. There's a PR that updates the docs for when v4 leaves beta, but at the moment npm install vue-jest will install v3, which has the tsConfig option.

[aantipov]

OK, didn't know about that PR, thanks for the clarification