Migrate to monorepo to split Vue 2 and Vue 3 packages

Related #343

Currently, the structure of this repository is as follows:

Branch	Version	Vue	Jest
master	4.x	2.x	<27
next	5.x(alpha)	3.x	<27

In Jest 27, breaking changes have came. (#344, #348, #351) To accommodate it, this package also requires breaking changes. (and need to increment semver)

But, vue-jest@4 cannot increment because of 5.x exists. So we should split it to another package.

If you want to keep the package name different, I don’t think it is necessary to divide the version by branch. (ex. CI/CD)

@lmiller1990 Could you tell us your thoughts on the items in the “Consideration” section?

Details

Package naming & Support version

Package	Ver.	Vue ver.	Jest ver.	Description
vue-jest	4.x	2.x	<27	alias for vue2-jest@26
vue-jest	5.x(alpha)	3.x	<27	deprecate (use vue3-jest@26 instead)
vue-jest	27.x	latest (=2.x now)	27.x	alias for vue2-jest@27 now
vue2-jest	26.x	2.x	26.x	equals to vue-jest@4
vue3-jest	26.x	3.x	26.x	equals to vue-jest@5
vue2-jest	27.x	2.x	27.x
vue3-jest	27.x	3.x	27.x

Versioning

Like ts-jest, We DOES NOT use Semantic Versioning.

[e-mail]
[e-mail]

• xx: Equals supported Jest major version
• yy: Compliant with semVer major & patch version (ie included BREAKING CHANGE)
• zz: Compliant with semVer patch version

It is recommended for users to pin version as below:

"devDependencies": {
  "vue2-jest": "^27.1.1", // Not recommended. It means 27.1.1 <= x < 28.0.0
  "vue2-jest": "27.1.x", // 27.1.0 <= x < 27.2.0
  "vue2-jest": "~27.1", // 27.1.0 <= x < 27.2.0
  "vue2-jest": "~27.1.1" // 27.1.1 <= x < 27.2.0
}

Repository Structures

• .github/
• e2e/
  • 2.x/
  • 3.x/
• packages/
  • vue2-jest/
    • src/
    • test/
    • package.json
    • README.md
  • vue3-jest/
    • src/
    • test/
    • package.json
    • README.md
  • core/
    • src/
    • test/
    • package.json
• .editorconfig
• .eslintrc
• .prettierignore
• LICENSE
• package.json
• README.md
• yarn.lock

Tasks

1. Add missing dependencies in /e2e projects
   • master branch (#356)
   • next branch (#357)
2. Setup monorepo in master branch (#360)
   • move vue-jest@4 library to /packages/vue2-jest
   • rename package to vue2-jest
   • move end-to-end tests to /e2e/2.x
3. Setup monorepo in next branch (#361)
   • move vue-jest@5 library to /packages/vue3-jest
   • rename package to vue3-jest
   • move end-to-end tests to /e2e/3.x
4. Merge next branch into master (#363)
5. (Optional) Split duplicated code in another package (like /packages/vue-jest-core)
6. Create vue-jest package that wraps vue2-jest@latest
7. Add or update README
   • vue-jest
   • vue2-jest
   • vue3-jest
   • root
8. Release vue2-jest, vue3-jest, and vue-jest-core

Consideration (Resolved)

Package name

• vue2-jest, vue-jest
• vue2-jest, vue3-jest
• vue2-jest, vue3-jest, vue-jest(alias of vue3-jest)
• Other

Use semver or not

• Yes, we will release new packages as version 1.x. Major version does not match Jest version.
• No, like ts-jest, we will release new packages as version 27.x. Major version matches Jest version.

Deprecates vue-jest or not

• **Yes.
• No. use vue-jest as alias of latest Vue + Jest package (currently vue3-jest@latest)

[lmiller1990]

That would work too. I’m sure we can ask npm for the package name vue2-jest, but it’s probably easier to just publish under the vue org.

[lmiller1990]

Ok, those are both merged. What’s next? Let’s update the plan:

next (Vue 3) and master (Vue 2) branches is now using a monorepo thanks to @nogic1008. This should help us support multiple Vue versions better.

We will not use next anymore. master will target the latest version of Jest (in this case 27). It will have support for both Vue 2 and 3.

I think the next step is having master include support for both Vue 2 and 3.

So

1. Merge next into master. We need two packages: vue2-jest and vue3-jest. This will target Jest 27.
2. Make a new PR with the changes to support Jest 27. This will target master.
3. Fork master -> call the new branch 26.x
4. Merge Jest 27 support to master.
5. Release 6? new versions:

• vue-jest@27 (Vue 2, Jest 27)
• vue-jest@27 (Vue 2, Jest 27)
• vue2-jest@26
• vue2-jest@27,
• vue3-jest@26
• vue3-jest@27

Does this sound correct?