javascript bind

run

$ node test2.js
1
2
3
NaN
4

test2.js

var Counter = function () {
  this.count = 0;
  this.tick = function () {
    this.count++;
    console.log(this.count);
  }
};

var myCounter = new Counter();
myCounter.tick();
myCounter.tick();
myCounter.tick();
setTimeout(myCounter.tick, 1000)
setTimeout(myCounter.tick.bind(myCounter), 1000)