cypress/docs/source/api/utilities/promise.md

title, comments

title	comments
Cypress.Promise	false

Cypress automatically includes {% url 'Bluebird' https://github.com/petkaantonov/bluebird %} and exposes it as Cypress.Promise.

Instantiate a new bluebird promise.

Syntax

new Cypress.Promise(fn)

Usage

{% fa fa-check-circle green %} Correct Usage

new Cypress.Promise((resolve, reject) => { ... })

{% fa fa-exclamation-triangle red %} Incorrect Usage

new cy.Promise(...)  // Errors, cannot be chained off 'cy'

Examples

Use Cypress.Promise to create promises. Cypress is promise aware so if you return a promise from inside of commands like {% url .then() then %}, Cypress will not continue until those promises resolve.

Basic Promise

cy.get("button").then(function($button){
  return new Cypress.Promise(function(resolve, reject){
    // do something custom here
  })
})

Waiting for Promises

it("waits for promises to resolve", function(){
  var waited = false

  function waitOneSecond(){
    // return a promise that resolves after 1 second
    return new Cypress.Promise(function(resolve, reject){
      setTimeout(function(){
        // set waited to true
        waited = true

        // resolve with 'foo' string
        resolve('foo')
      }, 1000)
    })
  }

  cy.then(function(){
    // return a promise to cy.then() that
    // is awaited until it resolves
    return waitOneSecond().then(function(str){
      expect(str).to.eq('foo')
      expect(waited).to.be.true
    })
  })
})