1. Prototype chain inheritance

function Parent () {
  this.name = 'kevin';
}
Parent.prototype.getName = function () {
  console.log(this.name);
}
function Child () {
 
}
Child.prototype = new Parent();

var child1 = new Child();
 
console.log(child1.getName()) // kevin
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Question:

1. Attributes of the reference type are shared by all instances. 2

2. Borrow constructors (classical inheritance)

function Parent (name) {
  this.name = name;
}
 
function Child (name) {
  Parent.call(this, name);
}
 
var child1 = new Child('kevin');
 
console.log(child1.name); // kevin
 
var child2 = new Child('daisy');
 
console.log(child2.name); // daisy


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Disadvantages: Methods are defined in constructors and are created each time an instance is created.

3. Combinatorial inheritance

function Parent (name) {
  this.name = name;
  this.colors = ['red'.'blue'.'green'];
}
 
Parent.prototype.getName = function () {
  console.log(this.name)
}
 
function Child (name, age) {
 
  Parent.call(this, name);
   
  this.age = age;
 
}
 
Child.prototype = new Parent();
 
var child1 = new Child('kevin'.'18');
 
child1.colors.push('black');
 
console.log(child1.name); // kevin
console.log(child1.age); / / 18
console.log(child1.colors); // ["red", "blue", "green", "black"]
 
var child2 = new Child('daisy'.'20');
 
console.log(child2.name); // daisy
console.log(child2.age); / / 20
console.log(child2.colors); // ["red", "blue", "green"]


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4. Original type inheritance

function createObj(o) {
  function F(){}
  F.prototype = o;
  return new F();
}

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Parasitic inheritance

function createObj (o) {
  var clone = object.create(o);
  clone.sayName = function () {
    console.log('hi');
  }
  return clone;
}

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Parasitic combinatorial inheritance

function object(o) {
  function F() {}
  F.prototype = o;
  return new F();
}
 
function prototype(child, parent) {
  var prototype = object(parent.prototype);
  prototype.constructor = child;
  child.prototype = prototype;
}
 
// When we use:
prototype(Child, Parent);



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