Type Alias DeepInject<T, D>

DeepInject: T extends (infer U)[]
    ? DeepInject<U, D>[]
    : T extends ReadonlyArray<infer U>
        ? ReadonlyArray<DeepInject<U, D>>
        : T extends object
            ? { [K in keyof T]: T[K] extends object ? DeepInject<T[K], D> : T[K] } & {
                [K in Exclude<
                    { [K in keyof D]-?: {} extends Pick<D, K> ? K : never }[keyof D],
                    keyof T,
                >]?: D[K]
            } & {
                [K in Exclude<
                    { [K in keyof D]-?: {} extends Pick<D, K> ? never : K }[keyof D],
                    keyof T,
                >]-?: D[K]
            }
            : T

Deeply inject properties into an object tree.

Type Parameters

T
Target object type
D
Injected type

Since

1.1.0

Remarks

Injects properties from type D into every nested object within T. Handles arrays and readonly arrays by injecting into their element types.

Properties in T are never overwritten by properties from D.

Example

type Nested = { level_1: { level_2: { } } };
type Metadata = { metadata?: string };
type DeepIntersected = DeepIntersection< Nested, Metadata >;
// { level_1: { level_2: { metadata?: string }, metadata?: string }, metadata?: string }