JSON in JS (launch object deep copy)

Full name ：JavaScript Object Notation

JSON Is a string , A string format often used to transmit data over the network

Common string formats ：
querystring Query string “name=karen&pwd=abc123&count=20"

template Template string `<div styLe="">666</div>`
JSON    json character string ‘{"name " : " karen" , "its" : [ "heLLo" , "h5"]}’

JSON analysis

parse() Method Parse the string into objects

Anti parsing stringify() Parse the object into a string

Code display ：

<script>
            var re="JSON data "
            var obj=JSON.parse(re)
			console.log(re,obj)
            //"JSON data " JSON data 
			var obj={name:"karen"}
            console.log(obj)
            //{name:"karen"}
			var str=JSON.stringify(obj)
			console.log(str)
            //{"name":"karen"}
</script>

Launch object deep copy 1（ If there is no internal reference data or time regularity null Wait for data ）

Ask for obj2 Object and the obj={name : "karen"} It looks the same , But they are not the same object , Can't write obj2={name : "karen"}

<script>
    	    var obj={name:"karen"}	
            // Wrong way ：		
		    var obj2={}
			obj2.name=obj.name	
            console.log(obj2,obj==obj2)//true
            // It still points to the same memory space 
		    // The right way ：
			var str=JSON.stringify(obj)//'{"name":"karen"}'	
		    var obj2=JSON.parse(str)//{name:"karen"}	
			console.log(obj2,obj==obj2)//{name:"karen"}  //false
</script>

Object deep copy 2

<script>
                function deepcopy(data){
				 if(typeof(data)=="object"){
					 if(data.constructor==Date){
						 return new Date(data.getTime())
					 }
					 else if(data==null){
						 return null
					 }
					 else if(data.constructor==RegExp){
						  return new RegExp(data)
					 }
					 else if(data.constructor==Array){
						  var newArray=new Array()
						   for(var i=0;i<data.length;i++){
							   var temp=data[i]					   
							   newArray.push(arguments.callee(temp))
						   }
					 	   return newArray
					 }
					 else{
						 var newobj=new data.constructor() //new Object()
						 // Object.keys()
						 for (var key in data) {							
						 	newobj[key]=arguments.callee(data[key])
						 }
						 return newobj
					 }
				 }
				 else{
					return data 
				 }
			}
</script>