函数扩展

1、参数给定默认值

function fun (age = 18) {
  return age;
}

2、剩余参数

function fn(x, ...rest) {
  // x => 1;
  // rest => [2,3];
}
fn(1,2,3);

3、函数传参数的同时可以解构

3.1数组解构

function fn ([a,...rest]) {
  // a => 1;
  // rest => [2,3];
}
fn([1,2,3]);

3.2对象解构

function fn ({name,age}) {
  // name => 'Jake';
  //age => 12;
}
fn({name: 'Jake', age: 12});