^31 prototype interview questions

1、

 function A() {

        }
        A.prototype.n = 1
        var b = new A()
        A.prototype = { //A The prototype of is given a new object 
            n: 2,
            m: 3
        }
        var c = new A()
        console.log(b.n, b.m, c.n, c.m) //1 undefined 2 3

The relationship of each variable is shown in the figure ：

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2、

 function F(){}
        Object.prototype.a=function(){
            console.log('a.()')
        }
        Function.prototype.b=function(){
            console.log('b.()')
        }
        var f=new F()
        f.a()
        // f.b()  Report errors 
        F.a()
        F.b()

Just search according to the figure

 

Red ： Implicitly deliver

Blue ： Deliver... Explicitly

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