events-helpers.js 712 B

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  1. /**
  2. * @fileoverview A set of helper functions to make it easier to work
  3. * with events in async/await manner.
  4. */
  5. /**
  6. * @param {!EventTarget} target
  7. * @param {string} eventName
  8. * @return {!Promise<!Event>}
  9. */
  10. const waitForEvent = (target, eventName) => {
  11. return new Promise(resolve => {
  12. target.addEventListener(eventName, resolve, { once: true })
  13. })
  14. }
  15. /**
  16. * @param {!EventEmitter} emitter
  17. * @param {string} eventName
  18. * @return {!Promise<!Array>} With Event as the first item.
  19. */
  20. const emittedOnce = (emitter, eventName) => {
  21. return new Promise(resolve => {
  22. emitter.once(eventName, (...args) => resolve(args))
  23. })
  24. }
  25. exports.emittedOnce = emittedOnce
  26. exports.waitForEvent = waitForEvent