Svelte 4 compatibility

[PixievoltNo1]

Svelte 4 is here! This package could work with it with some minor changes.

Svelte 4 was restructured to be importable exclusively by package exports. To work with this, the plugin must require "svelte/compiler", dropping the file extension.

Additionally, you should add a note to the readme with the above Parcel docs link and asking users to enable package exports. Parcel otherwise can't import anything from Svelte 4 by default.

[fregante]

I think this is causing the error:

🚨 Build failed.

Error: Could not resolve module "svelte/compiler.js" from 
"./node_modules/parcel-transformer-svelte/index.js"

however once that require is fixed, I get this error, which seems to come from svelte itself, somehow:

🚨 Build failed.

@parcel/core: Failed to resolve 'svelte/internal' from './source/app.svelte'

  ./source/app.svelte:36:8
    35 |     for (const extension of extensions) {
  > 36 |       extension.shown = keywords.every(word =>
  >    |           ^
    37 |         extension.indexedName.includes(word)
    38 |       );

@parcel/resolver-default: Cannot load file './internal' from module 'svelte'

I only found this mention online:

• https://github.com/sveltejs/svelte-loader/issues/234#issuecomment-1607058996

The solution for this second issue is to add this to my package.json:

    "alias": {
        "svelte/why": "https://github.com/orlov-vo/parcel-transformer-svelte/issues/37",
        "svelte/internal": "./node_modules/svelte/src/runtime/internal/index.js"
    }

Edit:

Actually it's because Parcel doesn't use the exports map by default 🤦‍♂️

https://parceljs.org/blog/v2-9-0/#new-resolver

The config is even easier, I'll add it to my PR

    "@parcel/resolver-default": {
        "packageExports": true
    },

[fregante]

Since this package seems abandoned, I published a temporary v4-compatible package until someone picks it up again.

npm rm parcel-transformer-svelte
npm i parcel-transformer-svelte-v4

// .parcelrc
"transformers": {
    "*.svelte": ["parcel-transformer-svelte-v4"]
},