blob: a9629c8993056ae83a2469f2497ce3fcce01f389 (
plain)
1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
37
|
/** A non-empty readonly array; the type system guarantees index 0 exists. */
export type NonEmptyArray<T> = readonly [T, ...T[]]
/** Values that round-trip through JSON.stringify / JSON.parse. */
export type JsonValue =
| string
| number
| boolean
| null
| readonly JsonValue[]
| { readonly [key: string]: JsonValue | undefined }
/** Element type of a readonly array (e.g., `ElementOf<typeof MONTH_NAMES>`). */
export type ElementOf<T extends readonly unknown[]> = T extends readonly (infer E)[] ? E : never
/** Deep-readonly version of a structural type. */
export type DeepReadonly<T> = T extends (infer U)[]
? ReadonlyArray<DeepReadonly<U>>
: T extends Map<infer K, infer V>
? ReadonlyMap<DeepReadonly<K>, DeepReadonly<V>>
: T extends Set<infer U>
? ReadonlySet<DeepReadonly<U>>
: T extends object
? { readonly [K in keyof T]: DeepReadonly<T[K]> }
: T
/**
* Nominal / branded type: compile-time-only tag to distinguish otherwise
* structurally-equal types.
*
* type PersonId = Brand<string, 'PersonId'>
* type RelId = Brand<string, 'RelationshipId'>
*
* PersonId and RelId are still strings at runtime but aren't assignable
* to each other without an explicit cast.
*/
export type Brand<T, B extends string> = T & { readonly __brand: B }
|
