Write your own Cypress commands
You write Cypress custom command, for example for selecting DOM elements by data-cy attribute like this:
/**
* Adds custom command "cy.dataCy" to the global "cy" object
*
* @example cy.dataCy('greeting')
*/
Cypress.Commands.add('dataCy', (value) => cy.get(`[data-cy=${value}]`))Yet, TypeScript compiler and IntelliSense do not understand that you have added a new method to the global cy object.
To add the new method to the global cy you need to add a separate TypeScript file like cypress/support/index.d.ts and list the new cy methods there.
declare namespace Cypress {
interface Chainable {
/**
* Custom command to select DOM element by data-cy attribute.
* @example cy.dataCy('greeting')
*/
dataCy(value: string): Chainable<Element>
}
}From your JavaScript spec file, use a special triple slash directive to load the new file by relative path:
/// <reference path="../support/index.d.ts" />And the TypeScript and IntelliSense should be happy
As an example this spec includes 3rd party module cypress-wait-until. This module ships with its own TypeScript definition, which allows cy.waitUntil to work. Load the types from the support/index.d.ts file
// load the global Cypress types
/// <reference types="cypress" />
// load the 3rd party command definition for cy.waitUntil()
/// <reference types="cypress-wait-until" />
Tip: use JSDoc comments to document your commands.
A custom command can call an async function from the application, the resolved value will be automatically yielded to the next command or assertion in the test. See cypress/e2e/async-command.cy.js file.
