Analysis and solution of JS this loss

this Lost Cases

var obj = {
	name: "Mike",
	sayHi: function(){
		console.log(this.name + " say Hi !");
	}
}
setTimeout(obj.sayHi, 1000);// undefined say Hi

Because of the this Always point to its caller 1s after call sayHi yes window but window Not so much therefore by undefined

Solution

Nested functions

• setTimeout(function(){obj.sayHi()}, 1000);// undefined say Hi

Use bind modify this Point to

• setTimeout(obj.sayHi.bind(obj), 1000);// undefined say Hi