Questions
10 of 17
1Explain the concept of 'callback hell' and how to mitigate it.
2What is a Promise in JavaScript?
3Explain the three states of a Promise.
4How do you create a new Promise in JavaScript?
5What is the purpose of `Promise.resolve()` and `Promise.reject()`?
6How do you handle the result of a Promise?
7What is Promise chaining?
8How do you handle errors in a chain of Promises?
9What is the purpose of `Promise.all()`, `Promise.race()`, `Promise.any()`, `Promise.allSettled()`?
10How can you handle multiple Promises concurrently without using `Promise.all()`?
11What is the purpose of the `async` and `await` keyword in JavaScript??
12How do you handle errors when using `async/await`?
13Do all `async` functions return Promises? Why or why not?
14How does `Promise.finally()` work?
15How do you convert a callback-based function into a Promise-based function?
16What is the purpose of `Promise.promisify()`?
17How can you create a custom Promise with timeout functionality?
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10 / 17

How can you handle multiple Promises concurrently without using `Promise.all()`?

  1. 1

    Promise.race(): The first resolved Promise (or the first rejected one) will determine the outcome.

  2. 2

    promise.allSettled : Fulfills when all promises settle.

  3. 3

    promise.any(). Fulfils when any of the promises are fulfilled; rejects when all of the promises are rejected.