Hi there!

I'm Arisa, a freelance Full Stack Developer living in Germany🇩🇪

I'm developing Lilac, an online school with hands-on Frontend e-books and tutoring👩‍💻

Who is this article for?

• Anyone migrating Babel v7
• Anyone fails the test with an error below (Jest)
• Anyone needs to maintain an old project for about 2-3 years like this one

What was the error?

Here's the troublemaker I had👇

TypeError: Cannot read property 'bindings' of null

Yup, this mister was annoying as it was because test error was showing me that all the tests were failing because of one line with null value returns.

But the value which my test was pointing out had returned value when I debug.

Phew...!

Gotta stop blaming loop😑

Here is my environment.

  "devDependencies": {
    "@babel/preset-env": "^7.13.12",
    "babel-core": "^6.26.3",
    "babel-jest": "^26.0.1",
    "babel-preset-env": "^1.7.0",
    "css-loader": "^3.5.3",
    "eslint": "5.16.0",
    "eslint-config-airbnb": "^18.1.0",
    "eslint-loader": "^4.0.2",
    "eslint-plugin-import": "^2.20.2",
    "eslint-plugin-jsx-a11y": "^6.2.3",
    "eslint-plugin-react": "^7.20.0",
    "jest": "^26.0.1",
    "jest-localstorage-mock": "^2.4.2",
    "node-sass": "^4.14.1",
    "sass-loader": "^8.0.2",
    "style-loader": "^1.2.1",
    "webpack": "^4.43.0",
    "webpack-cli": "^4.5.0",
    "webpack-dev-server": "^3.11.0"
  },
  "dependencies": {
    "moment": "^2.24.0"
  }

A solution

Change your .babelrc config from this below

// 🙅‍♀️ not working
{
    "presets": [
      "env"
    ]
}

to this👇

// 🙆‍♀️ works
{
  "presets": [
    ["@babel/preset-env"]
  ]
}

And install @babel/preset-env as devDependencies.

$ yarn add --dev @babel/preset-env

All set.

Run a test again, it won't fail if you wrote the test correctly👍

Hope this blog post was something you were looking for!

Sources

• babel/babel (GitHub repo)
• env preset breaks on class in v7 alpha 20 #6186
• Upgrade to Babel 7: Cannot read property 'bindings' of null