Is Firing and Forgetting Promises in Node.js Acceptable?

Fire and Forget Promises in Node.js (ES7)

Asynchronous programming in Node.js often involves working with promises. Promises represent the eventual completion or failure of an asynchronous operation. In certain scenarios, you may want to initiate an asynchronous operation without waiting for its completion. This is referred to as "firing and forgetting" a promise.

Consider the following code snippet:

redisClientAsync.delAsync('key');
return await someOtherAsyncFunction();

Inside an async function, you can execute the first line without using await. This creates a promise and immediately discards it.

Is This Acceptable?

Yes, it is possible to execute asynchronous tasks in this manner. By firing and forgetting the promise, the two asynchronous functions (promise creation and the function someOtherAsyncFunction) will execute concurrently.

Handling Errors

One potential issue with this approach is that if the promise created by delAsync is rejected, you will not be notified. This can lead to unhandled rejections that eventually crash your process.

Alternatives for Ignoring Results

If you do not care about the result of an asynchronous operation, there are several ways to handle it:

• Void Operator: Use the void operator to discard the result:

  void (await someAsyncFunction());

• Catch and Ignore: Ignore exceptions by using the catch method with an empty handler:

  ... someAsyncFunction().catch(function ignore() {}) ...

• Parallel Execution: If you still want to wait for other asynchronous operations but don't care about the result of a specific one, use Promise.all with an array:

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

Conclusion

While it is possible to fire and forget promises in Node.js, it is important to be aware of the potential risks associated with ignoring rejections. Consider carefully whether you truly don't care about the outcome of an asynchronous operation before employing this technique. Additionally, there are alternative approaches available for handling results that are not of interest.

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