引用类型 相等问题

引用（复合）类型，相等问题，详见实例

//引用类型 相等问题

//两个空的新对象  指向的 是不同的 地址
console.log( {}==={} ); //false

//指向 同一个 对象
let obj1 = { a: 1};
let obj2 = obj1;

console.log(obj1 === obj2); //true

//引用类型 套 引用类型
let obj3 = {
  a: 1,
  children: {
    b: 2,
    c: 3
  }
}

let obj4 = obj3.children;
let obj5 = {
  b: 2,
  c: 3
}

console.log(obj4 === obj5);    //false
console.log(obj3.children === obj4);  //true

let obj6 = {
  a: 1,
  children: [ 2, 3 ]
}

let oArr7 = obj6.children;
let oArr8 = [ 2, 3 ];

console.log(oArr7 === oArr8);    //false
console.log(obj6.children === oArr7);  //true



//数组同理

console.log([] === []); //false

let arr1 = [1, 2];
let arr2 = arr1;
console.log(arr1 === arr2); //true

let arr3 = [ 0, [2, 3] ];
let arr4 = arr3[1];
let arr5 = [2, 3];
console.log(arr4 === arr5);   //false
console.log(arr3[1] === arr4); //true

let arr6 = [ 0, { a: 2, b: 3}];
let aObj7 = arr6[1];
let aObj8 = { a: 2, b: 3};
console.log(aObj7 === aObj8);   //false
console.log(arr6[1] === aObj7); //true