Exploring RetryWhen Functionality
This implementation may not align perfectly with RxJS conventions, but it serves as a good entry point for those looking to grasp the concept before diving into more advanced stream manipulation techniques.
The retryWhen operator generates a stream of error values that can be manipulated in various ways, such as ignoring them altogether. In this scenario, we utilize defer to establish local state (a counter) and then monitor these errors to tally specific occurrences.
new Observable(observer => {
observer.next(1);
observer.error({message: "something"});
return {unsubscribe: () => {/* Do Nothing*/}};
}).pipe(
retryWhen(errors => defer(() => {
let count = 0; // Initialize a unique state
return errors.pipe(
switchMap(err => {
if (err.message === "something" && count < 3){
count++;
return of(null);
}
return throwError(err);
})
)
}))
).subscribe({
next: v => console.log("Next: ", v),
error: e => console.log("Error: ", e),
complete: () => console.log("Complete")
});
This code snippet should produce the following output (Comments added for clarity):
Next: 1 // Initial emission before encountering an error
Next: 1 // Emission after first retry
Next: 1 // Emission after second retry
Next: 1 // Emission after third retry
Error: {"message":"something"} // Exceeded maximum retries, halting further attempts