Create parallel tasks in Node.js

I have a function in my Node projects which I want to run parallel, i.e, as multiple instances, in the multi-core systems

The function's code is kind of like this:

try {
   const doc = collection_name.findOne({ '_id': id });
   if (doc) {
     // process the doc
     process(doc);
   }
} catch (err) {
   collection_name.update( // update some fields);
}

Now, what I want is to create N instances of this method, where N is the number of core available in the system. I know that Node.js's module: Cluster and Child Process can be used here but I'm not exactly sure how I can implement them.

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