chore(breaking): remove regenerator-runtime injection

[thymikee]

Summary

An attempt to get rid of regenerator-runtime addition in setupFiles. It's currently not working, but wanted @SimenB to see what can be wrong.

Test plan

Fix automock test failures

[SimenB]

Why do we need the regenerator runtime at all? If it's our own code, shouldn't the babel transform add whatever it needs to transpile async? If it's for users, why can't they setup transpilation of async-await themselves?

[SimenB]

As for the test failures, the changed stack trace looks awesome! Not sure about the automock ones, I'll take a look

[thymikee]

I think it's there for historic reasons, to make Jest "just work" with Babel's generators but I'd need @cpojer to back this up.

With Babel 6 it required globally available regenerator-runtime, but since Babel 7 it looks like regenerator-runtime is hidden inside @babel/runtime and accessible through the plugin and users should use that? Why it's not included in the @babal/preset-env though?

[SimenB]

See #7599

[SimenB]

to make Jest "just work" with Babel's generators

Now that node 8+ supports async-await out of the box, I'm not sure this makes sense. Seems like people should configure Babel properly instead if they want node 6?

[thymikee]

Yup, agreed

[SimenB]

Should update the title of this PR, as well as update the changelog (marking it as breaking, I guess)

[codecov-io]

Codecov Report

Merging #7595 into master will decrease coverage by 0.07%.
The diff coverage is 100%.

@@            Coverage Diff             @@
##           master    #7595      +/-   ##
==========================================
- Coverage   68.24%   68.16%   -0.08%     
==========================================
  Files         251      251              
  Lines        9639     9634       -5     
  Branches        5        5              
==========================================
- Hits         6578     6567      -11     
- Misses       3059     3065       +6     
  Partials        2        2

Impacted Files	Coverage Δ
packages/jest-config/src/normalize.js	82.3% <100%> (-0.72%)	⬇️
packages/jest-runtime/src/index.js	75.51% <0%> (-1.48%)	⬇️

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[SimenB]

Woo, green 😀

[cpojer]

I'm ok with this change. @thymikee is indeed right, this was for making Babel and async/await work out of the box in the past. If this works fine with babel 7, I'm ok with it. Just make sure that if people compile async/await down to ES5 + regenerator runtime in their setup, this change won't break them (alternatively ask them to just drop the transform in the test environment, but it may require setup).

[SimenB]

Users who just use @babel/plugin-transform-regenerator will get this error:

But it's not Jest's fault that they do not include it - they'd get the same error when using webpack or whatever and opening their JS in chrome.

They should use @babel/preset-env instead, IMO, and I think it's fine to break them. Just me? 😅

[SimenB]

Adding @babel/plugin-transform-runtime works, which is mentioned in the docs: https://babeljs.io/docs/en/babel-plugin-transform-runtime#regenerator-aliasing

(just make sure to set sourceType to either script or unambiguous, otherwise the injected helper uses import)

module.exports = {
  plugins: [
    '@babel/plugin-transform-regenerator',
    '@babel/plugin-transform-runtime',
  ],
  sourceType: 'script',
};

An alternative to setting sourceType is to use @babel/plugin-transform-modules-commonjs

---

I'll push a test with that as an integration test

[hanzlahabib]

i am kind of stuck on this error, i have searched through many stackoverflow issues, and other github repos issues, couldn't find issue to resolve regeneratorRuntime is not defined
i even tried @SimenB solution but that throws new list of errors,
almost spent half day around this issue couldn't get to the solution

here is what i am trying to do,
this is how my babel.config.js looks like

const isTest = String(process.env.NODE_ENV) === 'test'
module.exports = {
presets: [
'@babel/preset-env',
{ modules: isTest ? 'commonjs' : false },
'@babel/preset-react',
],
env: {
test: {
presets: [
'@babel/preset-env',
'@babel/preset-react',
],
plugins: [
'@babel/plugin-proposal-class-properties',
'@babel/plugin-transform-modules-commonjs',
'babel-plugin-dynamic-import-node',
'syntax-dynamic-import',
'@babel/plugin-proposal-object-rest-spread',
'transform-class-properties',
],
},
},
}

and here is my jest test component file

import React from 'react';
import ReactDOM from 'react-dom'
import commonPage from '../../pages/common/commonPage';
import { mount, shallow, render } from '../../Enzyme';

test('test common page test', () =>{
const container = document.createElement('div');
ReactDOM(, container);
console.log(container)
})

after running npm test it throw
ReferenceError: regeneratorRuntime is not defined

tried many solutions but couldn't reach to solution
any body who wants to see package.json dependencies
here they are

{"name": "primer-react",
"version": "0.1.0",
"private": true,
"devDependencies": {
"@babel/core": "^7.1.6",
"@babel/plugin-proposal-object-rest-spread": "^7.0.0",
"@babel/plugin-transform-modules-commonjs": "^7.5.0",
"@babel/plugin-transform-runtime": "^7.5.5",
"@babel/preset-env": "^7.1.6",
"@babel/preset-react": "^7.0.0",
"@babel/runtime": "^7.0.0-beta.55",
"babel-plugin-syntax-dynamic-import": "^6.18.0",
"babel-plugin-transform-class-properties": "^6.24.1",
"concurrently": "3.6.0",
"enzyme": "^3.9.0",
"enzyme-adapter-react-16": "^1.13.1",
"eslint-config-airbnb": ### "^17.1.1",
"eslint-plugin-import": "^2.18.2",
"eslint-plugin-jsx-a11y": "^6.2.3",
"eslint-plugin-react": "^7.14.3",
"husky": "^3.0.2",
"identity-obj-proxy": "^3.0.0",
"jest-enzyme": "^7.0.2",
"lint-staged": "^9.2.1",
"moxios": "^0.4.0",
"prettier": "^1.18.2",
"pretty-quick": "^1.11.1",
"react-test-renderer": "^16.8.6",
"redux-immutable-state-invariant": "^2.1.0",
"redux-logger": "^3.0.6",
"regenerator-runtime": "^0.13.3"
},
"dependencies": {
"@babel/polyfill": "^7.4.4",
},
}

Sorry for bad formatting i am new i couldn't make it better then this

[hanzlahabib]

Thanks Allah my issue is fixed,
here's what worked for me

• installed @babel/transform-runtime as dev dependency

and added this in babel.config.js plugins object

["@babel/transform-runtime", {"regenerator": true }] ]

plugins: [
["@babel/transform-runtime", {"regenerator": true }] ],
]

[khanguslee]

Thanks Allah my issue is fixed,
here's what worked for me

• installed @babel/transform-runtime as dev dependency

and added this in babel.config.js plugins object

["@babel/transform-runtime", {"regenerator": true }] ]

plugins: [
["@babel/transform-runtime", {"regenerator": true }] ],
]

@hanzlahabib Think you may have accidentally left out the word plugin in the library. Following this for steps:
Install @babel/plugin-transform-runtime as a dev dependancy

npm install --save-dev @babel/plugin-transform-runtime

Install @babel/runtime as a dependancy

npm install @babel/runtime

Then chuck this into your babel configuration:

{
    "plugins": [
        [
            "@babel/plugin-transform-runtime",
            {
                "regenerator": true
            }
        ]
    ]
}

[shinkathe]

I don't understand in what circumstance "@babel/plugin-transform-runtime" needs to be included? This error occurs for us when using react-table's useAsyncDebounce inside a jest test, but I don't know if the correct way to address this issue is to install transform-runtime, or to make some alterations to which node we are targeting - what exactly is the set of tooling/configuration that we should have where this issue does not occur?

[SimenB]

I don't understand in what circumstance "@babel/plugin-transform-runtime" needs to be included?

When you transpile async-await syntax.

Either leave async-await alone, or make sure to include the runtime.

---

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