dev mode times out if it imports a function called "then"

[samuelstroschein]

Astro Info

Astro                    v5.1.7
Node                     v22.11.0
System                   macOS (arm64)
Package Manager          npm
Output                   static
Adapter                  none
Integrations             none

If this issue only occurs in one browser, which browser is a problem?

No response

Describe the Bug

The astro dev mode times out.

• build && preview works fine
• the bug seems to occur with larger JS files.
• a plain vite project has no issue.

Bug emerged in opral/inlang-paraglide-js#313

What's the expected result?

Dev mode does not time out.

Link to Minimal Reproducible Example

https://github.com/samuelstroschein/astro-slow-dev-mode

Participation

• I am willing to submit a pull request for this issue.

[ascorbic]

This is such a great bug! I haven't found the root cause, but I'm pretty sure I know what it will look like. Anyway: the workaround is to remove the three exports of the function then(), from messages.js, en.js and de.js. The reason this is happening is almost certainly that somewhere there is somethign that checks if an import is async by seeing if it has a then() export. This is a really common approach, because the interface for "Thenables" is so loose. Something is looking at that import, thinking it's a promise, then waiting for it to resolve (which it never does, because then() isn't a promise callback). I'll see if I can find where this is happening, but it's such an edge case I would suggest you just rename that string for now.

[samuelstroschein]

Indeed. I created opral/inlang-paraglide-js#331 to forbid then as the message name. Feel free to close this issue or keep it open.

[riderx]

Thanks both for that ! Unexpected issue, but clearly my fault !
I’m so glad you found it i will be able to remove my custom implementation !