Buy me a coffee

We can trace NodeJS GC by using

  node --trace-gc app.js

And use the performance tool to get the data in runtime.

  const { PerformanceObserver } = require('perf_hooks');
  
  // Create a performance observer
  const obs = new PerformanceObserver((list) => {
    const entry = list.getEntries()[0]
    /* 
    The entry would be an instance of PerformanceEntry containing
    metrics of garbage collection.
    For example:
    PerformanceEntry {
      name: 'gc',
      entryType: 'gc',
      startTime: 2820.567669,
      duration: 1.315709,
      kind: 1
    }
    */
  });
  
  // Subscribe notifications of GCs
  obs.observe({ entryTypes: ['gc'] });
  
  // Stop subscription
  obs.disconnect();

To gather memory usage we can use the following code

  console.log(process.memoryUsage());
  // Prints:
  // {
  //  rss: 4935680,
  //  heapTotal: 1826816,
  //  heapUsed: 650472,
  //  external: 49879,
  //  arrayBuffers: 9386
  // }