Modern mode still doesn't work on typescript

[archseer]

Version

3.0.4

Node and OS info

latest

Steps to reproduce

yarn build --modern

What is expected?

The -legacy and regular bundle should be different sizes, and the regular one should contain arrow functions.

What is actually happening?

Files are almost identical apart from the sourcemap.

-rw-r--r--   1 speed  staff   394K Sep 19 18:49 app-legacy.49d50903.js
-rw-r--r--   1 speed  staff   394K Sep 19 18:50 app.b75421a2.js

I also can't find the arrow function used anywhere in the modern bundle:

$ rg "=>" app.b75421a2.js
(empty)

d6d2af5 took a stab at fixing this issue, but it seems to not be resolved.

[LinusBorg]

Can't reproduce:

Checked bundle content, modern one contains sync keyword, legacy one doesn't.

[archseer]

Alright, trying to build a minimal repro case

[archseer]

@LinusBorg Ok so I went and generated a new project with this preset:

{
  "packageManager": "yarn",
  "presets": {
    "ts": {
      "useConfigFiles": true,
      "plugins": {
        "@vue/cli-plugin-babel": {},
        "@vue/cli-plugin-typescript": {
          "classComponent": true,
          "useTsWithBabel": true
        },
        "@vue/cli-plugin-pwa": {},
        "@vue/cli-plugin-eslint": {
          "config": "airbnb",
          "lintOn": [
            "save"
          ]
        },
        "@vue/cli-plugin-unit-jest": {},
        "@vue/cli-plugin-e2e-nightwatch": {}
      },
      "router": true
    }
  },
  "useTaobaoRegistry": false
}

Then I copied my package.json and removed packages one by one.

Adding vuepress as a dependency to package.json makes modern mode stop working. (I followed the guide here to add it to an existing project: https://vuepress.vuejs.org/guide/getting-started.html#inside-an-existing-project)

I need it included in package.json because I'm sharing some of the components/dependencies with the main app, but I don't want vuepress to mess with my regular vue build.

[LinusBorg]

Great, can you put the project that you tested it with up on github? Then we can be sure we are doing the same thing.

[archseer]

Here: https://github.com/archSeer/tsmodern

yarn build --modern

Search for arrowTest inside app.*.js (not .map)

[{key:"arrowTest",value:function(){return function(){}}}]

Now remove vuepress from package.json, run yarn install, then yarn build --modern and it will work correctly again.

[archseer]

I think the typescript tag can be removed since it's a vuepress issue apparently, also maybe I should re-open the issue on the vuepress repo?

[LinusBorg]

Yes please. Close it here and re-open in their repository.

Thanks!