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eslint-plugin-cypress
Advanced tools
The eslint-plugin-cypress npm package provides a set of linting rules specific to Cypress, an end-to-end testing framework. These rules help developers adhere to best practices and avoid common mistakes when writing Cypress tests.
Enforcing Assertions
Ensures that assertions are made in test cases to prevent tests that mistakenly pass without asserting any conditions.
expect(something).to.be.true;
Disallowing Assignment in Conditional Expressions
Prevents the use of assignment operators in conditional expressions, which can lead to tests that pass incorrectly due to an assignment rather than a proper comparison.
if (user = getUser()) { /* ... */ }
Disallowing Unnecessary Waiting
Discourages the use of arbitrary wait times in tests, promoting the use of Cypress's built-in waiting mechanisms that are more reliable and efficient.
cy.wait(5000);
This package provides linting rules for Jest, another popular testing framework. It is similar to eslint-plugin-cypress in that it offers a set of rules tailored to the specific testing framework to encourage best practices.
Similar to eslint-plugin-cypress, this package offers linting rules for Mocha, a test framework for Node.js and the browser. It helps maintain code quality and adherence to Mocha-specific conventions.
This package is designed for linting code that uses the Testing Library family of utilities. It provides rules that help enforce best practices when writing tests with Testing Library, similar to how eslint-plugin-cypress does for Cypress tests.
An ESLint plugin for your Cypress tests.
Note: If you installed ESLint globally then you must also install eslint-plugin-cypress
globally.
Prerequisites: ESLint v7
, v8
or v9
.
This plugin supports the use of Flat config files with ESLint 8.57.0
and above.
npm install eslint-plugin-cypress --save-dev
or
yarn add eslint-plugin-cypress --dev
The use of ESLint v7
with eslint-plugin-cypress
is deprecated and support will be removed in a future version of this plugin. ESLint v7
reached end-of-life on Apr 9, 2022 and users are encouraged to migrate to ESLint v9
. See ESLint Version Support for ESLint's current release lines.
If you are using ESLint v7
or v8
, then add an .eslintrc.json
file to the root directory of your Cypress project with the contents shown below. You can continue to use this format with ESLint v9
if you set the ESLINT_USE_FLAT_CONFIG
environment variable to false
(see ESLint v9 > Configuration Files (Deprecated).
ESLint v9
uses a Flat config file format with filename eslint.config.*js
by default. Please refer to additional Flat config installation and configuration details. (You may also use this with ESLint 8.57.0
.)
{
"plugins": [
"cypress"
]
}
You can add rules:
{
"rules": {
"cypress/no-assigning-return-values": "error",
"cypress/no-unnecessary-waiting": "error",
"cypress/assertion-before-screenshot": "warn",
"cypress/no-force": "warn",
"cypress/no-async-tests": "error",
"cypress/no-async-before": "error",
"cypress/no-pause": "error",
"cypress/no-debug": "error"
}
}
You can allow certain globals provided by Cypress:
{
"env": {
"cypress/globals": true
}
}
Use the recommended configuration and you can forego configuring plugins, rules, and env individually. See below for which rules are included.
{
"extends": [
"plugin:cypress/recommended"
]
}
You can disable specific rules per file, for a portion of a file, or for a single line.
Disable the cypress/no-unnecessary-waiting
rule for the entire file by placing this at the start of the file:
/* eslint-disable cypress/no-unnecessary-waiting */
Disable the cypress/no-unnecessary-waiting
rule for only a portion of the file:
it('waits for a second', () => {
...
/* eslint-disable cypress/no-unnecessary-waiting */
cy.wait(1000)
/* eslint-enable cypress/no-unnecessary-waiting */
...
})
Disable the cypress/no-unnecessary-waiting
rule for a specific line:
it('waits for a second', () => {
...
cy.wait(1000) // eslint-disable-line cypress/no-unnecessary-waiting
...
})
You can also disable a rule for the next line:
it('waits for a second', () => {
...
// eslint-disable-next-line cypress/no-unnecessary-waiting
cy.wait(1000)
...
})
For more, see the ESLint rules documentation.
These rules enforce some of the best practices recommended for using Cypress.
💼 Configurations enabled in.
✅ Set in the recommended
configuration.
Name | Description | 💼 |
---|---|---|
assertion-before-screenshot | require screenshots to be preceded by an assertion | |
no-assigning-return-values | disallow assigning return values of cy calls | ✅ |
no-async-before | disallow using async /await in Cypress before methods | |
no-async-tests | disallow using async /await in Cypress test cases | ✅ |
no-debug | disallow using cy.debug() calls | |
no-force | disallow using force: true with action commands | |
no-pause | disallow using cy.pause() calls | |
no-unnecessary-waiting | disallow waiting for arbitrary time periods | ✅ |
require-data-selectors | require data-* attribute selectors | |
unsafe-to-chain-command | disallow actions within chains | ✅ |
Cypress is built on top of Mocha and Chai. See the following sections for information on using ESLint plugins eslint-plugin-mocha and eslint-plugin-chai-friendly together with eslint-plugin-cypress
.
.only
and .skip
During test spec development, Mocha exclusive tests .only
or Mocha inclusive tests .skip
may be used to control which tests are executed, as described in the Cypress documentation Excluding and Including Tests. To apply corresponding rules, you can install and use eslint-plugin-mocha. The rule mocha/no-exclusive-tests detects the use of .only
and the mocha/no-skipped-tests rule detects the use of .skip
:
npm install --save-dev eslint-plugin-mocha
In your .eslintrc.json
:
{
"plugins": [
"cypress",
"mocha"
],
"rules": {
"mocha/no-exclusive-tests": "warn",
"mocha/no-skipped-tests": "warn"
}
}
Or you can simply use the cypress/recommended
and mocha/recommended
configurations together, for example:
{
"extends": [
"plugin:cypress/recommended",
"plugin:mocha/recommended"
]
}
no-unused-expressions
Using an assertion such as expect(value).to.be.true
can fail the ESLint rule no-unused-expressions
even though it's not an error in this case. To fix this, you can install and use eslint-plugin-chai-friendly.
npm install --save-dev eslint-plugin-chai-friendly
In your .eslintrc.json
:
{
"plugins": [
"cypress",
"chai-friendly"
],
"rules": {
"no-unused-expressions": 0,
"chai-friendly/no-unused-expressions": 2
}
}
Or you can simply add its recommended
config:
{
"extends": ["plugin:chai-friendly/recommended"]
}
Please see our Contributing Guideline which explains how to contribute rules or other fixes and features to the repo.
FAQs
An ESLint plugin for projects using Cypress
The npm package eslint-plugin-cypress receives a total of 2,465,840 weekly downloads. As such, eslint-plugin-cypress popularity was classified as popular.
We found that eslint-plugin-cypress demonstrated a healthy version release cadence and project activity because the last version was released less than a year ago. It has 3 open source maintainers collaborating on the project.
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