Type Alias Properties<T>

Properties: IsAny<
    T,
    {
        $else: IsUnknown<T, { $else: { [k in keyof T]: T[k] }; $then: T }>;
        $then: T;
    },
>

Extracts the property map of a type: an object type with the same keys and value types as T, preserving optional and readonly modifiers.

For object types: returns { [k in keyof T]: T[k] }.
For any and unknown: returns the input type unchanged.
For function types (e.g. () => void): returns {} because call signatures are not indexable; for Function, returns the interface of methods.
For intersections: merges properties from all branches.

Type Parameters

T
The type whose properties to extract.

Example

type T = { a: number; b?: string }
type R = Properties<T> // { a: number; b?: string }

type Merged = Properties<{ a: 1 } & { b: 2 }> // { a: 1; b: 2 }