Type Alias OverrideProperties<TOriginal, TOverride>

OverrideProperties: Merge<TOriginal, TOverride>

Override existing properties of the given type. Similar to Merge, but enforces that the original type has the properties you want to override.

This is useful when you want to override existing properties with a different type and make sure that these properties really exist in the original.

Type Parameters

  • TOriginal
  • TOverride extends {
        [Key in keyof TOverride]: Key extends keyof TOriginal
            ? TOverride[Key]
            : never
    }

Example

type Foo = {
	a: string
	b: string
}
type Bar = OverrideProperties<Foo, {b: number}>
//=> {a: string, b: number}

type Baz = OverrideProperties<Foo, {c: number}>
// Error, type '{ c: number; }' does not satisfy the constraint '{ c: never; }'

type Fizz = OverrideProperties<Foo, {b: number; c: number}>
// Error, type '{ b: number; c: number; }' does not satisfy the constraint '{ b: number; c: never; }'

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