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Component Testing Config

When you launch Cypress for the first time in a project, the app will automatically guide you through setup and configuration. You don't need to do anything additional to get started.

Refer to the "Framework Configuration" guide in each UI framework's overview guide for a list of supported development servers and how they are configured.

Below are more advanced configuration options you can customize to fit your project.

Custom Dev Server

A custom function can be passed into the devServer option, which allows the use of other dev servers not provided by Cypress out of the box. These can be from the Cypress community, preview builds not included with the app, or a custom one you create.

The function's signature takes in a Cypress Configuration object as its only parameter and returns either an instance of a devServer or a promise that resolves to a devServer instance.

const { defineConfig } = require('cypress')

module.exports = defineConfig({
component: {
devServer(cypressConfig) {
// return devServer instance or a promise that resolves to
// a dev server here
return {
port: 1234,
close: () => {},

Custom Index File

By default, Cypress renders your components into an HTML file located at cypress/support/component-index.html.

The index file allows you to add in global assets, such as styles, fonts, and external scripts.

You can provide an alternative path to the file using the indexHtmlFile option in the component config options:

component: {
indexHtmlFile: '/custom/path/to/component-index.html'

Spec Pattern for Component Tests

By default, Cypress looks for spec files anywhere in your project with an extension of .cy.js, .cy.jsx, .cy.ts, or .cy.tsx. However, you can change this behavior for component tests with a custom specPattern value. In the following example, we've configured Cypress to look for spec files with those same extensions, but only in the src folder or any of its subdirectories.

component: {
specPattern: 'src/**/*.cy.{js,jsx,ts,tsx}'

Additional Config

For more information on all the available configuration options, see the configuration reference.