关于call,apply,bind的用法区别
call,apply,bind三个方法都是用来改变this指向的call与appl会立刻调用函数,bind不会立刻调用函数,而是把一个函数作为返回值返回
一:call()函数,第一个参数为this即将指向的对象,第二个是可能要传的参数举个栗子
let obj1 = {
name:"Jimmy",
age:15,
sayHi(){
console.log("Nice to meet you,my name is "+this.name)
},
eat(food,drink){
console.log(this.name+" like eat "+food+" "+drink)
}
}
let obj2 = {
name:"Harry",
age:16
}
obj1.sayHi.call(obj2)//Nice to meet you,my name is Harry
obj1.eat.call(obj2,"pizza","cola")//Harry like eat pizza cola
sayHi()方法的this,通过call指向了obj2eat()方法的this,通过call指向了obj2,并且传递了两个参数"pizza","cola"
二:apply函数,和call几乎一模一样,只需把"pizza","cola"两个参数以数组形式传递即可
obj1.eat.apply(obj2,["pizza","cola"])//Harry like eat pizza cola
三: bind()函数,和call也是几乎一模一样,不同的是,bind会返回一个函数,才可以使用
let fun = obj1.eat.apply(obj2,"pizza","cola")
fun()
总结:call,apply会立即执行,bind不会
转载自:https://segmentfault.com/a/1190000042396520