function baz (fn,obj) {
return function(){
return fn.apply(obj,arguments);
}
}
function foo(){
console.log(this.a);
}
var a = 3;
var obj = {
a:5
}
var bar = baz(foo,obj);
var b = bar();
console.log(b);
之前this指向window，输出结果为3，用了bind后，输出结果为5
文章来源: https://blog.csdn.net/weixin_44934978/article/details/90643085