// eventloop 事件循环机制// console.log('555');setTimeout(() => {console.log('666');})let p = new Promise((resolve,reject)=>{// 同步执行console.log('111');resolve();});// promise 的回调函数是异步的微任务p.then(v => {console.log('222');}, r => {console.log(r);});p.then(v => {console.log('444');})console.log('333');