Progress capturing

Progress capturing and cancellation

Basic example (Live demo):

import CPromise from 'c-promise';

const delay= (ms, value)=>{
  return new CPromise((resolve, reject, {onCancel}) => {
      const timer = setTimeout(resolve, ms, value);
      onCancel(() => {
          clearTimeout(timer);
          console.log('clear timeout');
      }) // clear internal operations on 'cancel' event
  })
}

const promise = CPromise.all([
  delay(1000, 'a'),
  delay(2000, 'b'),
  delay(3000, 'c'),
  delay(4000, 'd'),
  delay(5000, 'e'),
])
  .progress(value=> console.log(`Progress: ${(value * 100).toFixed(1)}%`));

console.log('isPromise:', promise instanceof Promise); // true

(async()=>{
 try {
     console.log(`Done: `, await promise);
 }catch(err){
     console.warn(`Failed: ${err}`);
     console.log('isCanceled:', promise.isCanceled);
 }
})()

setTimeout(()=> promise.cancel(), 3100); // cancel the promise after 3100ms

Console output:

isPromise: true
Progress: 20.0%
Progress: 40.0%
Progress: 60.0%
clear timeout
clear timeout
isCanceled: true
Failed: CanceledError: canceled

Process finished with exit code 0