JavaScript Promises and Async/Await

What does Promise.all return when all input promises are resolved?

What happens if any promise passed to Promise.all rejects?

What is the primary function of Promise.allSettled?

How is an asynchronous function defined in JavaScript?

What must be used inside an async function to wait for a promise to resolve?

What is the outcome when an async function is executed?

What will be logged when executing the function defined as 'async function f() { return Promise.resolve(1); }'?

Which of the following statements about Promise.all is incorrect?

Promises

JavaScript's Promise.all handles multiple promises concurrently.
Promise.all takes an array of promises as input and returns a single promise.
The returned promise resolves only when all input promises resolve.
If any input promise rejects, the returned promise immediately rejects.
Resolved values of all promises (if the returned promise resolves) are returned in an array.
Promise.allSettled() returns an array of objects. Each object has a "status" (fulfilled or rejected) and the corresponding value or reason for each promise. It waits for all promises to settle, unlike Promise.all which rejects immediately if one promise rejects.

Async/Await

Async/await simplifies asynchronous operations.
The async keyword designates a function as asynchronous.
An async function returns a promise.
The await keyword pauses execution until a promise resolves inside an async function.
Only use await inside an async function.
await causes the JavaScript engine to pause execution of the async function until the promise is either fulfilled or rejected and return the result instead of using then chains. If it is rejected, an error is thrown.

This quiz covers essential concepts of JavaScript promises, including the behavior of Promise.all and Promise.allSettled. It also explores the async/await syntax for managing asynchronous operations more easily. Test your understanding of how these features simplify coding with asynchronous JavaScript.