Cypress ESLint Plugin

An ESLint plugin for your Cypress tests.

Note: If you installed ESLint globally then you must also install eslint-plugin-cypress globally.

Installation

Prerequisites: ESLint v9. Lower versions are no longer supported.

npm install eslint eslint-plugin-cypress --save-dev

or

yarn add eslint eslint-plugin-cypress --dev

Usage

ESLint v9 uses a Flat config file format with filename eslint.config.*js by default. For instructions on using a deprecated eslintrc-type config file from previous ESLint versions, please refer to the ESLINTRC-CONFIG document.

To set up a flat configuration, add a file eslint.config.mjs to the root directory of your Cypress project and include the following instructions to import the available flat configurations using:

import pluginCypress from 'eslint-plugin-cypress/flat'

Configurations

There are two specific flat configurations available:

| Configuration | Content | | --------------------- | ----------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------- | | configs.globals | defines globals cy, Cypress, expect, assert and chai used in Cypress test specs as well as globals.browser and globals.mocha from globals. This version no longer specifies languageOptions for ecmaVersion and sourceType - see ESLint JavaScript languageOptions. There are no default rules enabled in this configuration. | | configs.recommended | enables recommended Rules. It includes also configs.global (see above). |

Rules

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 | ✅ |

Usage examples

In the following sections, different examples of possible configuration file contents are given, together with some brief explanations. Adapt these examples according to your needs.

Cypress

All rules from eslint-plugin-cypress are available through eslint-plugin-cypress/flat and can be individually activated.

• cypress/unsafe-to-chain-command is activated and set to error

import pluginCypress from 'eslint-plugin-cypress/flat'
export default [
  {
    plugins: {
      cypress: pluginCypress
    },
    rules: {
      'cypress/unsafe-to-chain-command': 'error'
    }
  }
]

Cypress recommended

The eslint-plugin-cypress recommended rules configs.recommended are activated, except for

• cypress/no-unnecessary-waiting which is set to off

import pluginCypress from 'eslint-plugin-cypress/flat'
export default [
  pluginCypress.configs.recommended,
  {
    rules: {
      'cypress/no-unnecessary-waiting': 'off'
    }
  }
]

Cypress globals

The configs.globals are activated.

import pluginCypress from 'eslint-plugin-cypress/flat'
export default [
  pluginCypress.configs.globals
]

Disable rules

You can disable specific rules per file, for a portion of a file, or for a single line. See the ESLint rules documentation. For example ...

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)
  ...
})

Mocha and Chai

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.

Mocha .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.

Cypress and Mocha recommended

eslint-plugin-mocha is added to the example Cypress recommended. This plugin offers a flat file recommended option configs.flat.recommended.

The settings for individual mocha rules from the configs.flat.recommended option are changed.

• mocha/no-exclusive-tests and mocha/no-skipped-tests are set to error instead of warn
• mocha/no-mocha-arrows is set to off instead of error

npm install eslint-plugin-mocha@^10.5.0 --save-dev

import pluginMocha from 'eslint-plugin-mocha'
import pluginCypress from 'eslint-plugin-cypress/flat'
export default [
  pluginMocha.configs.flat.recommended,
  pluginCypress.configs.recommended,
  {
    rules: {
      'mocha/no-exclusive-tests': 'error',
      'mocha/no-skipped-tests': 'error',
      'mocha/no-mocha-arrows': 'off',
      'cypress/no-unnecessary-waiting': 'off'
    }
  }
]

Cypress and Chai recommended

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.

eslint-plugin-chai-friendly is combined with the Cypress plugin eslint-plugin-cypress.

The recommended rules for both plugins are used: pluginCypress.configs.recommended and pluginChaiFriendly.configs.recommendedFlat:

npm install eslint-plugin-chai-friendly@^1.0.1 --save-dev

import pluginCypress from 'eslint-plugin-cypress/flat'
import pluginChaiFriendly from 'eslint-plugin-chai-friendly'
export default [
  pluginCypress.configs.recommended,
  pluginChaiFriendly.configs.recommendedFlat,
  {
    rules: {
      'cypress/no-unnecessary-waiting': 'off',
    },
  }
]

Contributing

Please see our Contributing Guideline which explains how to contribute rules or other fixes and features to the repo.