@japa/expect-type

Write assertions for TypeScript types

The expect-type plugin of Japa helps you write assertions against the TypeScript types. There is no runtime behavior with the expect-type plugin and you need to compile your code to view the assertion errors.

The plugins wraps expect-type under the hood.

Complete API documentation

Installation

Install the package from the npm registry as follows:

1npm i @japa/expect-type

1yarn add @japa/expect-type

Usage

You can use this package with the @japa/runner as follows.

1import { expectTypeOf } from '@japa/expect-type'
2import { configure } from '@japa/runner'
3
4configure({
5  plugins: [expectTypeOf()],
6})

Once done, you will be able to access the expectTypeOf property on the test context.

1test('test title', ({ expectTypeOf }) => {
2  expectTypeOf({ foo: 'bar' }).toEqualTypeOf<{ foo: string }>()
3})