AssertEqual

Since 1.3.0

Assert that type T equals Expected at compile time.

Signature

type AssertEqual<T, Expected> = (() => T extends Expected
  ? Expected extends T
    ? 1
    : 2
  : 2) extends () => 1
  ? T
  : never

Parameters

Parameter	Description
T	The type to check
Expected	The expected type to match

Examples

Basic Usage

import type { AssertEqual } from 'uni-types'

type Result = AssertEqual<string, string> // string
type Failed = AssertEqual<string, number> // never

With Object Types

type Obj = { name: string }
type Result = AssertEqual<Obj, { name: string }> // { name: string }

In Type Tests

type Test = AssertEqual<'hello' | 'world', 'world' | 'hello'> // 'hello' | 'world'

Related

• AssertExtends - Assert type extends another
• AssertKeyof - Assert key exists on type