cypress_js_polling_function.js

// usage: 
// cy.poll({
//   fn: () => cy.request(...),
//   until: response => response.body.count === 1,
//   assertFn: response => expect(response.body).to.deep.eq({
//     count: 1,
//   }),
//   timeout: 120000,
//   interval: 10000,
// })

function poll({
  fn, until, assertFn, timeout = 15000, interval = 3000,
}) {
  const endTime = Number(new Date()) + timeout
  const isTimeElapsed = () => Number(new Date()) > endTime;
  (function _poll() {
    fn().then((resp) => {
      if (until(resp) || isTimeElapsed()) {
        assertFn(resp)
      } else {
        cy.wait(interval).then(_poll)
      }
    })
  }())
}

export default poll