### **展开** ``` var arr = [1,2,3,4,5,6,7]; var arr2 = 8; var total = [...arr,arr2]; console.log(total); ``` ### **解构** ``` var obj = { name:"xiao", age:18 } var {name,age} = obj; console.log(name); ``` ### **默认赋值** ``` function go(a=20,b=40){ console.log(a+b); } go(); go(10,30) ```