https://stackoverflow.com/questions/20018588/how-to-monitor-the-memory-usage-of-node-js/64550489#64550489

node-mem.js

const formatMemoryUsage = (data) => `${Math.round(data / 1024 / 1024 * 100) / 100} MB`;

const memoryData = process.memoryUsage();

const memoryUsage = {
  rss: `${formatMemoryUsage(memoryData.rss)} -> Resident Set Size - total memory allocated for the process execution`,
  heapTotal: `${formatMemoryUsage(memoryData.heapTotal)} -> total size of the allocated heap`,
  heapUsed: `${formatMemoryUsage(memoryData.heapUsed)} -> actual memory used during the execution`,
  external: `${formatMemoryUsage(memoryData.external)} -> V8 external memory`,
};

console.log(memoryUsage);

/*
{
  "rss": "177.54 MB -> Resident Set Size - total memory allocated for the process execution",
  "heapTotal": "102.3 MB -> total size of the allocated heap",
  "heapUsed": "94.3 MB -> actual memory used during the execution",
  "external": "3.03 MB -> V8 external memory"
}
*/