Setup

caution

jest-extended only supports Jest version 27.2.5 and newer. If you're using an older version of Jest, use 1.2.1.

Create a setup script with the following:

// ./testSetup.js

// add all jest-extended matchers
import * as matchers from 'jest-extended';
expect.extend(matchers);

// or just add specific matchers
import { toBeArray, toBeSealed } from 'jest-extended';
expect.extend({ toBeArray, toBeSealed });

Add your setup script to your Jest setupFilesAfterEnv configuration. See for help

"jest": {
  "setupFilesAfterEnv": ["./testSetup.js"]
}

To automatically extend expect with all matchers, you can use

"jest": {
  "setupFilesAfterEnv": ["jest-extended/all"]
}