While loop using bluebird promises

by

cast can be translated to resolve. defer should indeed not be used.

You’d create your loop only by chaining and nesting then invocations onto an initial Promise.resolve(undefined).

function promiseWhile(predicate, action, value) {
    return Promise.resolve(value).then(predicate).then(function(condition) {
        if (condition)
            return promiseWhile(predicate, action, action());
    });
}

Here, both predicate and action may return promises. For similar implementations also have a look at Correct way to write loops for promise. Closer to your original function would be

function promiseWhile(predicate, action) {
    function loop() {
        if (!predicate()) return;
        return Promise.resolve(action()).then(loop);
    }
    return Promise.resolve().then(loop);
}

More Related Contents:

  1. What is the explicit promise construction antipattern and how do I avoid it?
  2. How do I convert an existing callback API to promises?
  3. How do I access previous promise results in a .then() chain?
  4. Aren’t promises just callbacks?
  5. When is .then(success, fail) considered an antipattern for promises?
  6. Is “.then(function(a){ return a; })” a no-op for promises?
  7. Correct way to write loops for promise.
  8. Asynchronous exception handling with bluebird promises
  9. What is the promise disposer pattern?
  10. Object method with ES6 / Bluebird promises
  11. Handling multiple catches in promise chain
  12. Limit concurrency of promise being run
  13. How do I tell if an object is a Promise?
  14. How to check if an object is a Promise?
  15. Catching Errors in JavaScript Promises with a First Level try … catch
  16. Slowdown due to non-parallel awaiting of promises in async generators
  17. resolving an array of promises from within a parent promise
  18. Are there still reasons to use promise libraries like Q or BlueBird now that we have ES6 promises? [closed]
  19. Promise.resolve vs new Promise(resolve)
  20. How do I use Bluebird with Angular?
  21. How do I handle errors with promises?
  22. Placement of catch BEFORE and AFTER then
  23. How can I promisify the MongoDB native Javascript driver using bluebird?
  24. When would someone need to create a deferred?
  25. How to promisify Node’s child_process.exec and child_process.execFile functions with Bluebird?
  26. Wait promise inside for loop
  27. How to extract data out of a Promise
  28. Limit concurrency of pending promises
  29. How do you properly promisify request?
  30. Is it possible to use axios.all with a then() for each promise?

Leave a Comment