eslint throws `no-undef` errors when linting Jest test files

I'm using Jest to write some specs and ESLint to lint the styling.

For my foo.spec.js tests, eslint keeps throwing the following errors. It seems to think that jest, beforeEach, afterEach, etc... are not defined in that file.

   11:1   error  'beforeEach' is not defined  no-undef
12:3   error  'jest' is not defined        no-undef
14:13  error  'jest' is not defined        no-undef
18:1   error  'afterEach' is not defined   no-undef
20:1   error  'describe' is not defined    no-undef
21:3   error  'it' is not defined          no-undef
25:5   error  'expect' is not defined      no-undef
28:5   error  'expect' is not defined      no-undef
31:5   error  'expect' is not defined      no-undef
34:3   error  'it' is not defined          no-undef
38:5   error  'expect' is not defined      no-undef
41:5   error  'jest' is not defined        no-undef
42:5   error  'expect' is not defined      no-undef
43:5   error  'expect' is not defined      no-undef
46:3   error  'it' is not defined          no-undef
54:5   error  'expect' is not defined      no-undef
58:5   error  'jest' is not defined        no-undef

I believe those are included by jest automatically and so they don't need to be explicitly imported in my spec files. In fact the only thing I import via my jest.setup.js file is

import "react-testing-library/cleanup-after-each";
import "jest-dom/extend-expect";

Is there a way to eliminate these errors without having to disable eslint rules at the top of each individual file or inline?

Thanks!

36382

小开

最佳答案

Please, add the following to your .eslintrc file:

{
"overrides": [
{
"files": [
"**/*.spec.js",
"**/*.spec.jsx"
],
"env": {
"jest": true
}
}
]
}

小开

Had a similar problem with eslint throwing no-undef errors for my jest setup.js file with some jest.mocks in it.

Ended up fixing it by using the ESLint plugin for Jest.

After installing the plugin as a dev dependency, I merged the following into my .eslintrc config file per instructions from the plugin readme.

{
"extends": ["plugin:jest/recommended"],
"plugins": ["jest"]
}

Then the no-undef errors are gone.

小开

You do not need to add this override option and specify in which files jest should be available. Adding only env field should be enough.

.eslintrc.js:

module.exports = {
env: {
jest: true
},
//...
}