This code sample is used to explain how to find memory leaks in Node.js in this post: https://stackoverflow.com/questions/66473378/memory-leaks-in-node-js-how-to-analyze-allocation-tree-roots

memory-leak-example.js

// ###########################################################################
// util
// ###########################################################################

const N = 100e6;

// async function sleep(ms) { return new Promise(r => setTimeout(r, ms)); }

/**
 * 
 * @param {number} N number of bytes
 * @param {[]} a the array to add pressure to
 */
function addPressure(a) {
  console.log('adding pressure', N)

  // NOTE: padStart does not allow that big a number, so we have to run it multiple times.
  const S = 100e6;
  const I = Math.ceil(N / S);
  for (let i = 0; i < I; ++i) {
    const s = ''.padStart(S, 'l') + 'x';
    a.push(s);

    // NOTE: random access into the string actually allocates it
    // console.log(
    a.map(s => s[S / 2] + s.length).join(', ')
    // );
  }
}

function gc() {
  global.gc();
  console.log('gc');
}


// ###########################################################################
// run test
// ###########################################################################


let a;
function test1() {
  const b = [];
  addPressure(b);
  a = b;
  gc();
}







test1();

debugger;