jest.polyfills.js

// jest.polyfills.js
/**
 * @note The block below contains polyfills for Node.js globals
 * required for Jest to function when running JSDOM tests.
 * These HAVE to be require's and HAVE to be in this exact
 * order, since "undici" depends on the "TextEncoder" global API.
 *
 * Consider migrating to a more modern test runner if
 * you don't want to deal with this.
 */
import 'web-streams-polyfill/polyfill'
if (typeof global.BroadcastChannel === 'undefined') {
  global.BroadcastChannel = class {
    constructor(channel) {
      this.channel = channel
    }
    postMessage(message) {}
    close() {}
  }
}
const {TextDecoder, TextEncoder, ReadableStream} = require('node:util')

Object.defineProperties(globalThis, {
  TextDecoder: {value: TextDecoder},
  TextEncoder: {value: TextEncoder},
  ReadableStream: {value: ReadableStream},
})

const {Blob, File} = require('node:buffer')
const {fetch, Headers, FormData, Request, Response} = require('undici')

Object.defineProperties(globalThis, {
  fetch: {value: fetch, writable: true},
  Blob: {value: Blob},
  File: {value: File},
  Headers: {value: Headers},
  FormData: {value: FormData},
  Request: {value: Request},
  Response: {value: Response},
})