laxels aoc-2024 .cursorrules file for TypeScript

<rule>
When checking if something is `null` or `undefined` in JavaScript/TypeScript, use `== null` and `!= null` explicitly, like so:
```
const value = map.get(key);
if (value == null) {
  return;
}
```

Only use the "check if truthy/falsy" form when explicitly handling non-null falsy values:
```
const value = map.get(key);
// Also guard against falsy values like `0` or empty string in addition to `null`/`undefined`.
if (!value) {
  return;
}
```
</rule>

<rule>
The error variable in a try/catch should be named `err`.
</rule>

<rule>
When working with `vitest`:
- Prefer `.toStrictEqual()` over `.toEqual()`.
- Always use `expect`, `onTestFinished`, and `onTestFailed` from the test context instead of module imports.
</rule>

<rule>
The `tsconfig` has `noUncheckedIndexedAccess: true`, so always account for `undefined` values when doing indexed accesses on objects/arrays.
</rule>

<rule>
Prefer arrow functions when defining anonymous functions.
</rule>

<rule>
Instead of using drizzle's `inArray`, use `safeInArray` imported  from '$lib/server/db/util' instead.
</rule>

<rule>
When writing HTML (including in components), use Tailwind CSS.
</rule>

<rule>
When importing from '$lib/db/schema' or '$lib/route', use namespace imports like so:
```
import * as s from '$lib/db/schema';
import * as r from '$lib/route';
```
</rule>

<rule>
When importing from a built-in Node.js module, use the 'node:' prefix, like so:
```
import { Readable } from 'node:stream';
```
</rule>

<rule>
When converting an iterable to an array, prefer `[...iterable]` over `Array.from(iterable)`
</rule>