console.log('1')
async function async1() {
await async2()
console.log('async1 end')
}
async function async2() {
console.log('async2 end')
new Promise((resolve) => {
console.log('promise1')
resolve()
}).then(() => console.log('then1'))
.then(() => console.log('then2'))
await async3()
new Promise((resolve) => {
console.log('promise2')
resolve()
}).then(() => console.log('then3'))
.then(() => console.log('then4'))
}
async function async3() {
console.log('async3 end')
}
console.log('2')
async1()
console.log('3')
请教解决过程，其中我最不明白的是then3 async1 end then4这三个的输出顺序
