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<title>Document</title>
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<script>
// 判断b是否为空，为空就给默认值1
function add(a,b){
b=b||1;
return a+b;
}
console.log(add(10));//11
//现在这样写
function add1(a,b=1){
return a+b;
}
console.log(add1(20));//21
//不定参数
function fun(...values){
console.log(values.length)
}
fun(1,2,3);//3
fun(1,2,3,4,5);//5
//箭头函数
//以前的写法
var print=function(obj){
console.log(obj);
}
print(1234);
//现在
var print1 = obj=>console.log(obj);
print1(12345);
var sum2=(a,b)=> a+b;
console.log(sum2(11,22));
var sum3=(a,b)=>{
c=a+b;
return a+c;
}
console.log(sum3(10,20));
//解构
const person={
name:"jack",
age:21
}
function hello(person){
console.log("hello"+person.name);
}
var hello2=({name})=>console.log("hello"+name);
hello2(person);
</script>
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