JS written test question -- deep copy of object

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One 、 utilize JSON Method

The easiest way , The defect is that there is no copy of the prototype chain , Functions and null No copying

			var copy1 = function (obj) {
			    return JSON.parse(JSON.stringify(obj));
			}
			var a = {a:function(){console.log('hello world')},b:{c:1},c:[1,2,3],d:"wanger",e:new Date(),f:null,g:undefined}
			var b = copy1(a)
			console.log(a,b)

Two 、 Using self call of function

Full deep copy

            var copy1=function(obj){
				if(obj===null){return obj}
				if(typeof obj !== 'object'){return obj}
				if(obj.constructor==='Date'){return new Date(obj)}
				if(obj.constructor==='RegExp'){return new RegExp(obj)}
				var newObj=new obj.constructor()   // Maintain inheritance chain 
				for(var key in obj){
					if(obj.hasOwnProperty(key)){    // Do not traverse the attributes on its prototype chain 
					var val=obj[key];
				    newObj[key]=typeof val ==='object'?arguments.callee(val):val;   //  Use arguments.callee Decoupling from function names 
				}
			}
			return newObj;
			}
			var a = {a:function(){console.log('hello world')},b:{c:1},c:[1,2,3],d:"ljy",e:new Date(),f:null,g:undefined} 
			var b = copy1(a);
			console.log(a,b);