TypeError: require(...) is not a function

[devmetal]

TypeError: require(...) is not a function

What is the current behavior?

I try to create a simple wrapper around chokidar. Also i like to add some smoke tests with jest. I use flow types, and babel6 with flow and env presets.

This is my test code

/* eslint-env jest */

import fs from 'fs'
import path from 'path'
import watch from '../watch'

const testDir = path.join(__dirname, 'temp')
const testFile = path.join(testDir, 'test.txt')

describe('watch files in directory', () => {
  let watcher

  const onAdd = jest.fn()
  const onChange = jest.fn()
  const onUnlink = jest.fn()

  beforeAll(() => {
    fs.mkdirSync(testDir)

    watcher = watch(testDir)
    watcher.on('add', onAdd)
    watcher.on('change', onChange)
    watcher.on('unlink', onUnlink)
  })

  afterAll(() => {
    fs.rmdirSync(testDir)
  })

  describe('watch add event', () => {
    beforeAll(() => {
      fs.writeFileSync(testFile, 'Content')
    })

    it('on(\'add\') triggered', () => {
      expect(onAdd).toHaveBeenCalled()
    })
  })

  describe('watch change event', () => {
    beforeAll(() => {
      fs.appendFileSync(testFile, 'Changes')
    })

    it('on(\'change\') triggered', () => {
      expect(onChange).toHaveBeenCalled()
    })
  })

  describe('watch unlink event', () => {
    beforeAll(() => {
      fs.unlinkSync(testFile)
    })

    it('on(\'unlink\') triggered', () => {
      expect(onUnlink).toHaveBeenCalled()
    })
  })
})

This is the api:

// @flow

import chokidar from 'chokidar'

export type evt = 'add' | 'change' | 'unlink'

export interface WatchEvent {
  on(e: evt, handler: (path: string) => any): any;
}

export default (root: string): WatchEvent => {
  return chokidar.watch(root, {
    persistent: true,
    ignoreInitial: true
  })
}

Very simple, but with jest is can't start. When i start this with jest latest version, i get back this error:

/Users/uname/works/node/mylive/node_modules/readdirp/readdirp.js:55
    var api          =  require('./stream-api')();
                                               ^

TypeError: require(...) is not a function
    at readdir (/Users/uname/works/node/mylive/node_modules/readdirp/readdirp.js:55:48)
    at FSWatcher.<anonymous> (/Users/uname/works/node/mylive/node_modules/chokidar/lib/fsevents-handler.js:350:7)
    at /Users/uname/works/node/mylive/node_modules/graceful-fs/polyfills.js:287:18
    at FSReqWrap.oncomplete (fs.js:153:5)

But when i just start with babel build and simple node command, the api working as expected.

Please provide your exact Jest configuration

Not use any, just the .babelrc with env and flow presets.

Run npx envinfo --preset jest in your project directory and paste the
results here

npx: installed 1 in 4.267s

System:
OS: macOS High Sierra 10.13.4
CPU: x64 Intel(R) Core(TM) i5-7267U CPU @ 3.10GHz
Binaries:
Node: 8.11.1 - ~/.nvm/versions/node/v8.11.1/bin/node
Yarn: 1.5.1 - /usr/local/bin/yarn
npm: 5.6.0 - ~/.nvm/versions/node/v8.11.1/bin/npm
npmPackages:
jest: ^22.4.3 => 22.4.3

[SimenB]

The error is basically what #5888 tries to highlight, but due to the asynchronicity at play, it fails at a different place.

In your case the runtime stops here: https://github.com/facebook/jest/blob/4f64c4cfa951cc4c437a40650cec8d9b74735af8/packages/jest-runtime/src/index.js#L504-L507

The watchers are triggered asynchronously, and your synchronous code doesn't wait for it.

You can use something like https://www.npmjs.com/package/wait-for-expect to wait for the expect to pass, or just add a small timeout yourself

[SimenB]

We should really handle "someone is trying to use the jest-environment after it was torn down" better, though

[github-actions]

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