retryWhen

연산자(operator) 정의: retryWhen(receives: (errors: Observable) => Observable, the: scheduler): Observable

Retry an observable sequence on error based on custom criteria.

Examples

Example 1: Trigger retry after specified duration

( jsBin | jsFiddle )

//emit value every 1s
const source = Rx.Observable.interval(1000);
const example = source
  .map(val => {
    if(val > 5){
     //error will be picked up by retryWhen
     throw val;
    }
    return val;
  })
  .retryWhen(errors => errors
               //log error message
               .do(val => console.log(`Value ${val} was too high!`))
               //restart in 5 seconds
               .delayWhen(val => Rx.Observable.timer(val * 1000))
            );
/*
  output: 
  0
  1
  2
  3
  4
  5
  "Value 6 was too high!"
  --Wait 5 seconds then repeat
*/
const subscribe = example.subscribe(val => console.log(val));

Additional Resources

• retryWhen - Official docs
• Error handling operator: retry and retryWhen - André Staltz

Source Code: https://github.com/ReactiveX/rxjs/blob/master/src/operator/retryWhen.ts