const promise = new Promise((resolve, reject) => {
console.log(1);
resolve(5);
console.log(2);
}).then(val => {
console.log(val);
});
promise.then(() => {
console.log(3);
});
console.log(4);
setTimeout(function() {
console.log(6);
});
//执行顺序为1,2,4,5,3,6
promise里为同步,reslove为异步,then为异步,setTimeout为最后
js中Promise是同步还是异步?then呢?
未经允许不得转载:阿锋哥前端开发经验分享 » js中Promise是同步还是异步?then呢?