let g1 = gen();
g1.next() //{value:'hello',done:false}
g1.next() //{value:'world',done:false}
g1.next() //{value:'hello world',done:true}//使用for...of循环for(let value of g1){
}
//解构赋值
let [a,b] =gen() //a--hello,b--world
let [a,b,c]=gen() //c--undefined//剩余参数
let[a,...b]=gen()
//扩展运算符
...gen() //hello world
Array.form(gen()) //[hello,world]