四.原型式继承（Object.create）
let parent4 = { name: "parent4", friends: ["p1", "p2", "p3"], getName: function() { return this.name; } }; let person4 = Object.create(parent4); person4.name = "tom"; person4.friends.push("jerry"); let person5 = Object.create(parent4); person5.friends.push("lucy"); console.log(person4.name); // tom console.log(person4.name === person4.getName()); // true console.log(person5.name); // parent4 console.log(person4.friends); // ["p1", "p2", "p3","jerry","lucy"] console.log(person5.friends); // ["p1", "p2", "p3","jerry","lucy"]毛病：浅拷贝，多个实例的援用类型属性指向雷同的内存
五. 寄生式继承
let parent5 = { name: "parent5", friends: ["p1", "p2", "p3"], getName: function() { return this.name; }};function clone(original) { let clone = Object.create(original); clone.getFriends = function() { return this.friends; }; return clone;}let person5 = clone(parent5);let person6 = clone(parent5);person5.name = '22';person5.friends.push(22);console.log(person5.getName()); // parent5console.log(person5.getFriends()); // ["p1", "p2", "p3", 22]console.log(person6.getName()); // parent5console.log(person6.getFriends()); // ["p1", "p2", "p3", 22]毛病：浅拷贝，多个实例的援用类型属性指向雷同的内存
六.寄生组合式继承 (全场最佳）
function clone (parent, child) { // 这里改用 Object.create 就能够缩小组合继承中多进行一次结构的过程 child.prototype = Object.create(parent.prototype); child.prototype.constructor = child;}function Parent6() { this.name = 'parent6'; this.play = [1, 2, 3];}Parent6.prototype.getName = function () { return this.name;}function Child6() { Parent6.call(this); this.friends = 'child5';}clone(Parent6, Child6);Child6.prototype.getFriends = function () { return this.friends;}let person6 = new Child6(); console.log(person6); //{friends:"child5",name:"child5",play:[1,2,3],__proto__:Parent6}console.log(person6.getName()); // parent6console.log(person6.getFriends()); // child5