Alloc error

alloc.js

var bigInt = 1000000000;

console.log(process.argv);

function asBuf() {
  var buf = new Buffer("");

  for (var i = 0; i < bigInt; i++) {
    if (i % 10000 == 0) console.log(process.memoryUsage()['rss'] / 1024 / 1024 + 'mb');
    buf = Buffer.concat([buf, new Buffer("a")]);
  }  
}

function asArr() {
  var arr = [];

  for (var i = 0; i < bigInt; i++) { 
    if (i % 10000 == 0) console.log(process.memoryUsage()['rss'] / 1024 / 1024 + 'mb');
    arr.push("a");
  }
}

if (process.argv[2] == '--buffer') { asBuf(); } else { asArr(); }