ArrayConcat.md

typelab / utils / ArrayConcat

type ArrayConcat<T1, T2> = T1 extends ReadonlyArray ? _IfNotAnyOrNever<T1, IfAny<T2, [...T1, Any], T2 extends ReadonlyArray ? [...T1, ...T2] : [...T1, T2]>> : never;

Concatenates two Array types into one.

Type Parameters

Type Parameter
T1
T2

Template

The first Array type to concatenate.

Template

The second Array type to concatenate.

Returns

A new Array type that is the result of concatenating A and B.

Example

// [string, number, boolean, object]
type Concatenated1 = ArrayConcat<[string, number], [boolean, object]>;

// [...string[], boolean, object]
type Concatenated2 = ArrayConcat<string[], [boolean, object]>;

// [string, number, ...object[]]
type Concatenated3 = ArrayConcat<[string, number], object[]>;

// [string, number, any]
type Concatenated4 = ArrayConcat<[string, number], any>;

// never
type Never = ArrayConcat<any, [string, number]>;