# Added a new slot in the dashboard, TypeScript says the slot ID does not exist

Asked by Josh Whitcomb on 2025-10-28. Tags: typescript, cli, errors.

Created a `promo-banner` slot in the dashboard ten minutes ago, referenced it in
code, and tsc is having none of it:

```
error TS2344: Type '"promo-banner@1"' does not satisfy the constraint
'VersionedSlotId'.
```

We run strict everything so I can't just cast my way out (nor would I want to).
I assume there is codegen somewhere that hasn't heard the news. What is the
blessed way to refresh it, and more importantly, how do I stop every dev on teh
team from tripping over this individually?

## 1 answer

### Accepted answer from Camille Fournier-Blanc (2025-10-28)

Your read is right: `slots.d.ts` is generated by the CLI and it does not watch
the dashboard. Creating a slot in the UI changes nothing on disk until you
regenerate.

For the immediate fix, run:

```croct-cmd
croct add slot
```

and pick `promo-banner`. That registers the slot in `croct.json5` and
regenerates the declarations, so `SlotContent<'promo-banner@1'>` starts
compiling.

For the team-wide problem, two habits solve it:

1. Commit the regenerated `slots.d.ts`. It is generated code, but committing it
   means checkouts and CI builds type-check without needing an API fetch.
2. Run `npx croct install` once in the repo. It registers a postinstall hook
   that keeps the types in sync for everyone else on `npm install`, so the
   person who adds the slot is the only one who has to think about it.

After that, a stale-types incident requires someone to both add a slot and
forget to commit, which code review catches.

#### Reply from Josh Whitcomb (2025-10-29)

Regenerated, committed, postinstall hook added. Compiler is appeased.
Codegen that has to be manually poked will never not annoy me, but at least
the hook makes it someone else's problem exactly once.