What do the return values of node.js process.memoryUsage() stand for?

Question

From the official documentation (source):

process.memoryUsage()

Returns an object describing the memory usage of the Node

Answer 1

RSS is the resident set size, the portion of the process's memory held in RAM (as opposed to the swap space or the part held in the filesystem).

The heap is the portion of memory from which newly allocated objects will come from (think of malloc in C, or new in JavaScript).

You can read more about the heap at Wikipedia.