1. 物件引用

var a = {name:'wanger'}
var b = a ;
a===b // true
b.name = 'zhangsan'
a.name //'zhangan'

2 .淺拷貝

var a = {name:'wanger'}
var b = Object.assign({}, a)
a===b // false
b.name = 'zhangsan'
a.name //'wanger'

2.參考別人示例程式碼

var obj = {a: 1, b: 2, c: { a: 3 },d: [4, 5]}
var obj1 = obj
var obj2 = JSON.parse(JSON.stringify(obj))//深拷貝常用方法
var obj3 = {...obj}
var obj4 = Object.assign({},obj)
obj.a = 999
obj.c.a = -999
obj.d[0] = 123
console.log(obj1) //{a: 999, b: 2, c: { a: -999 },d: [123, 5]}
console.log(obj2) //{a: 1, b: 2, c: { a: 3 },d: [4, 5]}
console.log(obj3) //{a: 1, b: 2, c: { a: -999 },d: [123, 5]}
console.log(obj4) //{a: 1, b: 2, c: { a: -999 },d: [123, 5]}
 

var arr = [1, 2, 3, [4, 5], {a: 6, b: 7}]
var arr1 = JSON.parse(JSON.stringify(arr))//深拷貝常用方法
var arr2 = arr
var arr3 = [...arr]
var arr4 = Object.assign([],arr)
console.log(arr === arr1) //false
console.log(arr === arr2) //true
console.log(arr === arr3) //false
console.log(arr === arr4) //false
arr[0]= 999
arr[3][0]= -999
arr[4].a = 123
console.log(arr1) //[1, 2, 3, [4, 5], {a: 6, b: 7}]
console.log(arr2) //[999, 2, 3, [-999, 5], {a: 123, b: 7}]
console.log(arr3) //[1, 2, 3, [-999, 5], {a: 123, b: 7}]
console.log(arr4) //[1, 2, 3, [-999, 5], {a: 123, b: 7}]