原型链经典面试题

命题点一：原型基础 + 构造函数基础

var A = function() {};
A.prototype.n = 1;
var b = new A();
A.prototype = {
  n: 2,
  m: 3
}
var c = new A();

console.log(b.n);
console.log(b.m);

console.log(c.n);
console.log(c.m);
// 1、undefined、2、3

命题点二：自有属性与原型继承属性

function A() {
    this.name = 'a'
    this.color = ['green', 'yellow']
 }
 function B() {}
 B.prototype = new A()
 var b1 = new B()
 var b2 = new B()
 
 b1.name = 'change'
 b1.color.push('black')

console.log(b2.name) // 'a'
console.log(b2.color) // ["green", "yellow", "black"]

命题点三：构造函数综合考察