2.3.2.Allow node.js perform GC collection

• 1.sudo npm install heapdump

• 2.加入：

  require('heapdump');
  var leakyData = [];
  var nonLeakyData = [];
  
  function generateHeapDumpAndStats(){
    //1. Force garbage collection every time this function is called
    try {
      global.gc();
    } catch (e) {
      console.log("You must run program with 'node --expose-gc index.js' or 'npm start'");
      process.exit();
    }
  
    //2. Output Heap stats
    var heapUsed = process.memoryUsage().heapUsed;
    //console.log("Program is using " + heapUsed + " bytes of Heap.");
    debug("Program is using " + heapUsed + " bytes of Heap.");
    //3. Get Heap dump
    //process.kill(process.pid, 'SIGUSR2');
  }
  
  setInterval(generateHeapDumpAndStats, 2000);

• 3.在命令列中執行:

        node --expose-gc app.js

• 4.reference: http://www.alexkras.com/simple-guide-to-finding-a-javascript-memory-leak-in-node-js/