Will this play nicely with jest?

[Aaron-Pool]

First of all--thank you SO much. I've been hoping one of the core Vue members would backport script setup to Vue 2.

The only adoption concern I have left after reading the readme is whether this will break my jest tests. I guess it wouldn't be too hard for me to write a basic jest transform using the JavaScript API. But I wasn't sure whether that would play nicely with vue-jest. Any thoughts on this.

[antfu]

I think there should be no problem on that. /cc @lmiller1990 WDYT?

We could ships a simple jest transformer via submodules just like other plugins, tho I am not very familiar with jest, pr will be great welcome!

[Aaron-Pool]

@antfu I did a little digging, and it looks like running multiple transforms on the same file extension is a non-trivial problem.
See the discussion here: jestjs/jest#8725

So it seems like the PR would need to be to submitted to vue-jest, rather than here.

[antfu]

Or we could bypass the transform to vue-jest (as ppl are likely to use it when using jest), something like:

const { transform } = require('vue2-script-setup-transform')

module.exports = (source, id, ...args) {
  const transformed = transform(source, id)

  return require('vue-jest')(source, id, ...args)
}

[lmiller1990]

First off, I am amazed this has been ported to Vue 2. Well done! I haven't looked at how it's implemented exactly, but assuming there is no technical blocker, we could support this in vue-jest.

Considering Vue 2 will not have many more big updates, maintenance should not be too difficult. I am not sure I have time to work on this right now, but since most of the work is done in this code base, I'm guess we just:

• import this into vue-jest
• before we do the usual vue-jest transform, we pass the input to this module, changing the code into a regular SFC
• let vue-jest do the rest of the transform

[Neophen]

Ok so for those running into this issue here's the solution:

create a file vue-setup-transformer.js:

const { transform } = require('vue2-script-setup-transform');
const vueJest = require('vue-jest');

module.exports = {
  process(source, filename, ...args) {
    const transformed = transform(source, filename);
    return vueJest.process(transformed.code, filename, ...args);
  },
};

and then in your jest.config.js replace vue-jest with this custom transformer:

'.*\\.(vue)$': '<rootDir>/vue-setup-transformer.js',

I don't know where i could submit this PR or how to do it, but if you let me know i could most likely do a pr here or for vue-jest?

Edit:
This still seems to have trouble when transforming with external dependencies. it fails at the const transformed = transform(source, filename); and never goes into the vue-jest.process

Trying to figure out why

[antfu]

Glad to see it works!

v0.4.1 ships an experimental support for jest:

npm i -D vue-jest

// jest.config.js
module.exports = {
  transform: {
    '.*\\.(vue)$': 'unplugin-vue2-script-setup/jest',
  },
}

Let me know if it works for you

[Aaron-Pool]

@antfu is this gonna play havoc with source maps? I was actually planning to do a PR for this myself, but I ran into an issue where I wasn't sure how to properly handle combining the source map for this transform with the one vue-jest generates.

[Neophen]

@antfu i found a super weird issue

if you have the word link in a v-for item like so:

<div v-for="(link, index) in links" :key="index" class="py-4 space-y-2">

this will break the transformation with:

ERROR: Unexpected token (1:1)
STACK: SyntaxError: Unexpected token (1:1)

and it doesn't matter it could be just link or adminLink or linkItem it will always break

[Neophen]

This is actually not a problem with jest, but with the whole plugin, added more details here:
link to issue

[dm4t2]

@antfu I tried it with Jest like described in the README.md, but I get the following error:

Module unplugin-vue2-script-setup/jest in the transform option was not found.

There seems to be something missing in the bundle.

[sh786]

I am getting same as @dm4t2

[Aaron-Pool]

@dm4t2 @sh786 I ran into this as well. I'm sure @antfu will fix the issue as soon as he can, but until then, a simple work around is creating a sibling file to your jest config with the below contents:

// jest-script-setup-transform
const { transform } = require('unplugin-vue2-script-setup');

module.exports = {
  process(source, filename, ...args) {
    const transformed = transform(source, filename);
    const code = transformed ? transformed.code : source;
    return require('vue-jest').process.call(this, code, filename, ...args);
  },
};

and then using it like you would the real transform:

// jest.config.js
module.exports = {
  // with your other config options
  transforms: {
    '.*\\.(vue)$': require.resolve('./jest-script-setup-transform.js'),
  }
}

[dm4t2]

I've created a PR for this.

[dm4t2]

It still does not work for me. I tried it in a newly created Vue CLI project, but got the following error:

Any advice? Thanks!

[sh786]

It still does not work for me. I tried it in a newly created Vue CLI project, but got the following error:

Any advice? Thanks!

Same here

[AndrewBastin]

I tried to look into this and don't exactly understand what went wrong here, but on the generated index.js file the CommonJS export doesn't seem to be having the transform import where as it seems to exported properly in the ES module. I am not really familiar with the toolchain used here, but if I get time I will try to look into this and open a PR.

Meanwhile, the following hacky workaround snippet seems to work to get transform running for me in the meantime, just not a big fan of it.

// jest-script-setup-transform.js
const { raw } = require("unplugin-vue2-script-setup")

const transform = raw().transform

module.exports = {
  process(source, filename, ...args) {
    const transformed = transform(source, filename)
    const code = transformed ? transformed.code : source
    return require("vue-jest").process.call(this, code, filename, ...args)
  },
}

UPDATE: I created a separate empty node project, import this package, and try to run with the "type": "module" mode (basically enabling ESModule), even in that, the following snippet logs undefined

import { transform } from "unplugin-vue2-script-setup";

console.log(transform);

[wesley-spencer]

So is this fixed? Cause I believe I am running in to the same problems

[antfu]

I would suggest moving to https://github.com/vitest-dev/vitest, there isn't much space for us to support plugin transformations in jest properly