`$env/dynamic/public` isn't available in `hooks.client.js` in prod

[dmkret]

Describe the bug

Values from env from $env/dynamic/public should be available in hooks.client.js after build just like in other client-side code, but env is empty {}.

Reproduction

https://stackblitz.com/edit/sveltejs-kit-template-default-yf9uq9?file=src/hooks.server.js

1. Open browser terminal.
2. Run npm run build && npm run preview in stackblitz project terminal;
3. View into browser console.

Expected:

hooks.server.js: dynamic.PUBLIC_VARIABLE = value ✅
hooks.server.js: static.PUBLIC_VARIABLE = value ✅
hooks.client.js: dynamic.PUBLIC_VARIABLE = value ❌ // undefined
hooks.client.js: static.PUBLIC_VARIABLE = value ✅

Logs

hooks.server.js: dynamic.PUBLIC_VARIABLE = value
hooks.server.js: static.PUBLIC_VARIABLE = value
hooks.client.js: dynamic.PUBLIC_VARIABLE = undefined
hooks.client.js: static.PUBLIC_VARIABLE = value

System Info

System:
    OS: Linux 5.0 undefined
    CPU: (7) x64 Intel(R) Core(TM) i9-9880H CPU @ 2.30GHz
    Memory: 0 Bytes / 0 Bytes
    Shell: 1.0 - /bin/jsh
  Binaries:
    Node: 16.14.2 - /usr/local/bin/node
    Yarn: 1.22.19 - /usr/local/bin/yarn
    npm: 7.17.0 - /usr/local/bin/npm
  npmPackages:
    @sveltejs/adapter-auto: ^1.0.0 => 1.0.0 
    @sveltejs/kit: ^1.0.0 => 1.0.11 
    svelte: ^3.54.0 => 3.55.1 
    vite: ^4.0.0 => 4.0.4

Severity

annoyance

Additional Information

Workaround is accessing env inside root layout script.

[dummdidumm]

I fear we can't do much about this. Accessing env eagerly in the root means that it wasn't set at that time yet. If you do it lazily or inside a setTimeout you'll see it's defined then.

I tend to make this a documentation issue. An alternative solution could be to use await to import the client code dynamically after setting the environment. I'm not sure how much this has an impact on startup time thought, and if it's worth it fixing this.

[Rich-Harris]

I think we probably could fix it, no? We just need to set the env before importing the hooks. Adds some complexity but feels doable

[DoisKoh]

Go go merge ranger!