promise思考

Posted 2020-10-10 windSeek

let query;
query = (url) => {
    return new Promise((resolve,reject) => {
        setTimeout(() => {
            console.log(url);
            if(true){
                resolve(url);
            }else{
                reject();
            }

        }, 1000)
    }).catch((error)=>{console.log(error)});
};
query("test1")
    .then(query("test2"))
    .then(query("test3"))
let arrCreate=()=>{
    let arr=[];
    for(let i=1;i<11;i++){
        arr.push(query("test"+i));
    }
    return arr;
}
let arr=arrCreate();
Promise.all(arr)
    .then(()=>{console.log("promise 全部执行了")})
    .catch(function(error){console.log(error)});

以上是javascript中promise的链式操作demo