ES6对象扩展——扩展运算符

            //复制对象:使用扩展运算符复制对象时是浅拷贝
            const obj1 = {
                a:1,
                b:2,
                d:{
                    aa:1,
                    bb:2
                }
            }
            const obj2 = {
                c:3,
                a:9
            }
            const cObj1 = {...obj1};
            
            console.log(cObj1.d.aa); //1
            cObj1.d.aa = 999;
            console.log(cObj1.d.aa);  //999
            console.log(obj1.d.aa);   //999
            

                        //代码接上
            //合并对象:当有相同属性名时,保留靠后的那一个
            const newObj = {
                ...obj1,
                ...obj2
            };
            newObj.d.aa = 22;
            //合并对象时也是浅拷贝
            console.log(obj1);  //22