异步和同步
Visionwuwu 2020-05-31
javascript
# 面试题
js是门单线程语言，先执行主栈任务，再执行异步任务。本题考查宏任务和微任务，事件队列，事件循环机制。
async function async1(){
console.log('async1 start')
await async2()
console.log('async1 end')
}
function async2(){
console.log('async2')
}
console.log('script start')
setTimeout(_=>{
console.log('setTimeOut')
},0)
async1()
new Promise(resolve=>{
console.log('Promise1')
resolve()
}).then(res=>{
console.log('Promise2')
})
console.log('script end')
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解析
