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In our first example we will see how much memory is used by a very basic method: reverse(). Testing reverse() memory usage for a small array

external is, according to the documentation, the memory used by "C++ objects bound to JavaScript objects managed by V8"Īrmed with the knowledge we are ready to see some examples.

heapUsed is the actual memory used during the execution of our process.heapTotal is the total size of the allocated heap.rss stands for Resident Set Size, it is the total memory allocated for the process execution.MemoryUsage returns an object with various information: rss, heapTotal, heapUsed, external: Process is a global Node.js object which contains information about the current Node.js process, and it provides exactly what we were searching for: the memoryUsage() method. We know what the Resident Set is and we also know that the Heap is what we're looking for: now we need to find out how much heap is used by a given Node.js process. Sounds complicated? We need to focus only on the heap for now, so don't worry if you can't grasp all the terminology right now! Querying the Node.js heap Hopefully the following illustration will clarify the concept:

The Resident Set contains also the actual Javascript code (inside the Code segment) and the Stack, where all the variables live. You can think of it as of a big box which contains some more boxes. The heap is part of something bigger though: a running Node.js process store all its memory inside a Resident Set. The heap is a memory segment used for storing objects, strings and closures. How does Node.js organizes the memory?Ī blog post won't be enough to explain all the machinery: you should just be concerned about the heap for now so let's start by breaking down the basics. To follow along you need a basic understanding of Javascript and a Node.js installation. How to get information about the memory of a Node.js process.