What is the purpose of the `Promise.all()` method?

What is the purpose of the `Promise.all()` method?

• A. To execute promises in series
• B. To execute multiple promises concurrently and return a single promise
• C. To convert promises into callbacks
• D. To limit the number of concurrent promises

Answer: (B)

The `Promise.all()` method is designed to handle multiple promises concurrently and returns a single promise that resolves when all of the promises in the iterable have resolved or when the iterable contains no promises. This means that when using `Promise.all()`, you can initiate multiple asynchronous operations at once, allowing them to run simultaneously rather than sequentially. The promise returned by `Promise.all()` will fulfill if all the promises it contains succeed, and it will reject with the reason of the first promise that rejects. This behavior is particularly useful for scenarios where you need to wait for several asynchronous operations to complete before proceeding, and you want to optimize performance by running them in parallel instead of executing them sequentially. For instance, if you're fetching multiple resources from an API, using `Promise.all()` allows you to send all requests at once and then handle the responses together, improving the efficiency of your application. This capability is what distinguishes `Promise.all()` from other approaches that handle promises.

The Promise.all() method is designed to handle multiple promises concurrently and returns a single promise that resolves when all of the promises in the iterable have resolved or when the iterable contains no promises. This means that when using Promise.all(), you can initiate multiple asynchronous operations at once, allowing them to run simultaneously rather than sequentially.

The promise returned by Promise.all() will fulfill if all the promises it contains succeed, and it will reject with the reason of the first promise that rejects. This behavior is particularly useful for scenarios where you need to wait for several asynchronous operations to complete before proceeding, and you want to optimize performance by running them in parallel instead of executing them sequentially.

For instance, if you're fetching multiple resources from an API, using Promise.all() allows you to send all requests at once and then handle the responses together, improving the efficiency of your application. This capability is what distinguishes Promise.all() from other approaches that handle promises.