一、当async中只有一个await时的执行顺序
下面是async函数中只有一个await时 的例子
async function async1() {
console
.log("start")
await async2();
console
.log("async1 end")
}
async function async2(){
console
.log("async2 start");
}
async1();
console
.log("ending........")
打印结果：
start
async2 start
ending
......
async1 end
二、当asyan中有多个await时的执行顺序
下面展示`当有多个await存在时的打印顺序
function doSometing() {
console
.log("执行doSometing");
return "testSometing";
}
async function async2() {
console
.log("执行Async2");
return Promise
.resolve("hello async");
}
async function async1() {
console
.log("async1 start...");
const v1
= await doSometing();
console
.log(v1
);
const v2
= await async2();
console
.log(v2
);
console
.log(v1
, v2
);
}
async1();
console
.log("end......")
打印结果：
async1 start
...
执行doSometing
end
......
testSometing
执行Async2
hello
async
testSometing hello
async
三、async同级有new Promises时的执行顺序
async function async1() {
console
.log("start")
await async2();
console
.log("async1 end")
}
async function async2(){
console
.log("async2 start");
}
async1();
console
.log("ending........")
new Promise(function(resolve
){
console
.log("Promise1")
resolve();
}).then(function (){
console
.log("Promise1 end")
})
打印结果：
start
async2 start
ending
......
Promise1
async1 end
Promise1 end
四、当含有setTimeout函数时：
async function async1() {
console
.log("start")
await async2();
console
.log("async1 end")
}
async function async2(){
console
.log("async2 start");
}
async1();
setTimeout(function(){
console
.log("setTimeout 2")
},0)
new Promise(function(resolve
){
console
.log("Promise1")
resolve();
}).then(function (){
console
.log("Promise1 end")
})
console
.log("ending........")
打印结果：
start
async2 start
Promise1
ending
......
async1 end
Promise1 end
setTimeout
2
