const obj = {
a:1,
b:2,
c:3,
d:4,
e:5
}
const a = obj.a;
const b = obj.b;
const f = obj.a + obj.d;
这样太繁琐
用ES6的解构赋值来取值
const {a,b,c,d,e}=obj
const f = a+d