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

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

Usage

Add an .eslintrc.json file to your cypress directory with the following:

{
  "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"
  }
}

You can whitelist globals provided by Cypress:

{
  "env": {
    "cypress/globals": true
  }
}

Recommended configuration

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"
  ]
}

Rules

These rules enforce some of the best practices recommended for using Cypress.

Rules with a check mark (✅) are enabled by default while using the plugin:cypress/recommended config.

NOTE: These rules currently require eslint 5.0 or greater. If you would like support added for eslint 4.x, please 👍 this issue.

	Rule ID	Description
✅	no-assigning-return-values	Prevent assigning return values of cy calls
✅	no-unnecessary-waiting	Prevent waiting for arbitrary time periods
	no-force	Disallow using force: true with action commands
	assertion-before-screenshot	Ensure screenshots are preceded by an assertion
	require-data-selectors	Only allow data-* attribute selectors (require-data-selectors)

Chai and 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
  }
}

Contribution Guide

To add a new rule:

• Fork and clone this repository
• Generate a new rule (a yeoman generator is available)
• Run yarn start or npm start
• Write test scenarios then implement logic
• Describe the rule in the generated docs file
• Make sure all tests are passing
• Add the rule to this README
• Create a PR

Use the following commit message conventions: https://github.com/semantic-release/semantic-release#commit-message-format