SOURCE

let user = new Object() ;
user.name = 'zhanghongbo';
user.age = 30;

// 1.Object

// console.log(user.name)
// let key = 'name'
// console.log(user[key])
// for (key in user) {
//   // console.log(key)
//   console.log(user[key])
// }
// 
// console.log(JSON.stringify(user))

//2.
// let a = 'hello world'
// let b = a
// b = 'c'
// console.log(a)

// let a = '123'
// let b = '123'
// console.log('a==b:'+a==b?true:false)

// let clone = {}
// for(key in user)
// 	{
// 		clone[key] = user[key]
// 	}

// console.log("clone:" + JSON.stringify(clone))
// console.log('user==clone?:'+ (user == clone?true:false))


//3.reference
// let arr1 = [1,2,3]
// let arr2 = arr1
// arr2[0] = 4
// console.log(arr1)

//4.Object.assign
// let clone = {}
// Object.assign(clone,user,{name:'xxx'},{sex:'male'})
// console.log(JSON.stringify(clone))

//5