Function createLookup

createLookup<T>(
items: T[],
getKey: (item: T) => string,
): { get(id: string, version: number): T | undefined }
Creates a keyed lookup from an array of items. Items are indexed by a composite string key (typically "id:version"), and the returned object exposes a get(id, version) method that reconstructs the same key internally.

Use this to build the TClaimLookup required by ArgumentEngine's constructor from flat arrays (e.g. database query results).
Type Parameters
- T
Parameters
- items: T[]
  The array of items to index.
- getKey: (item: T) => string
  A function that produces the composite key for each item. Must return a string of the form "id:version" so that the returned get(id, version) method can reconstruct it.
Returns { get(id: string, version: number): T | undefined }
An object with a get(id, version) method that looks up items by reconstructing the composite key. Returns undefined if no item matches.
Example
```
const claimLookup = createLookup(claims, (c) => `${c.id}:${c.version}`)
const engine = new ArgumentEngine(arg, claimLookup, ...)
```
- Defined in src/lib/utils/lookup.ts:30