Should I Ignore Promises in Node.js?

Firing and Forgetting Promises in Node.js (ES7)

Background

In an asynchronous context, promises allow developers to perform tasks without blocking the main thread. However, concerns arise when you want to initiate an asynchronous operation but do not require its result or handle its potential errors.

Question

Can you simply call redisClientAsync.delAsync('key') without awaiting it or utilizing a callback? Moreover, is it acceptable to execute this asynchronous function alongside another one in an async function without awaiting the first one?

Answer

It is possible to initiate two asynchronous operations simultaneously by running the first one without awaiting it. However, this approach has its drawbacks:

1. Unhandled Rejection Risk:
If the first promise is rejected, you will not be alerted because you did not await it. This may lead to an unhandled rejection, which can crash your process if not properly handled.

2. Undefined Behavior:
You should explicitly define your intent when dealing with asynchronous operations. It is not recommended to initiate an asynchronous task without specifying whether you intend to wait for its result, handle its errors, or ignore it entirely.

Best Practices

Depending on your specific requirements, there are several options available:

1. Wait for Result but Ignore Value:
If you want to wait for side effects but do not need the result, you can dispose of it using void (await someAsyncFunction()).

2. Ignore Errors:
If you are not concerned about errors, you can utilize someAsyncFunction().catch(function ignore() {}) to dismiss them.

3. Execute in Parallel:
If you want to execute multiple asynchronous tasks concurrently and handle the results, you can use Promise.all as follows:

const [_, res] = await Promise.all([
    someAsyncFunction(), // result is ignored, exceptions aren't
    someOtherAsyncFunction()
]);

return res;

By employing these techniques, you can effectively handle asynchronous operations in Node.js (ES7) based on your specific needs.

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