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",
  }
}

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
	assertion-before-screenshot	Ensure screenshots are preceded by an assertion

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

Yproximite/eslint-plugin-cypress