Jittat: /* Async / await */

2020-07-05T18:13:48Z

Async / await

Jittat: สร้างหน้าด้วย "== Code เริ่มต้น == function doSomething(msg) { let t = Math.random()*1500; setTimeout(() => {..."

2020-07-05T18:13:06Z

สร้างหน้าด้วย "== Code เริ่มต้น == <syntaxhighlight lang="javascript"> function doSomething(msg) { let t = Math.random()*1500; setTimeout(() => {..."

หน้าใหม่

== Code เริ่มต้น ==
<syntaxhighlight lang="javascript">
function doSomething(msg) {
let t = Math.random()*1500;
setTimeout(() => {
console.log(msg + " " + t);
}, t);
}

console.log("----started----");
doSomething("A ");
doSomething(" B ");
doSomething(" C ");
doSomething(" D ");
doSomething(" E ");
console.log("---------------");
</syntaxhighlight>

== Callback ==
<syntaxhighlight lang="javascript">
function doSomething(msg, callback) {
let t = Math.random()*1500;
setTimeout(() => {
console.log(msg + " " + t);
if (callback !== undefined) callback();
}, t);
}

console.log("----started----");
doSomething("A ", () => {
doSomething(" B ", () => {
doSomething(" C ", () => {
doSomething(" D ", () => {
doSomething(" E ");
});
});
});
});
console.log("---------------");
</syntaxhighlight>

== Promise ==
<syntaxhighlight lang="javascript">
function doSomething(msg) {
return new Promise((resolve,reject) => {
let t = Math.random()*1500;
setTimeout(() => {
console.log(msg + " " + t);
resolve();
}, t);
});
}

console.log("----started----");
doSomething("A ")
.then(() => {return doSomething(" B ")})
.then(() => {return doSomething(" C ")})
.then(() => {return doSomething(" D ")})
.then(() => {return doSomething(" E")});
console.log("---------------");
</syntaxhighlight>

== Async / await ==
<syntaxhighlight lang="javascript">
function doSomething(msg) {
return new Promise((resolve,reject) => {
let t = Math.random()*1500;
setTimeout(() => {
console.log(msg + " " + t);
resolve();
}, t);
});
}

async function main() {
await doSomething("A ");
await doSomething(" B ");
await doSomething(" C ");
await doSomething(" D ");
await doSomething(" E");
return 10;
}

function main2() {
return (main()
.then((x) => { return doSomething(" Z " + x); }));
}

async function main2alternative() {
let x = await main();
await doSomething(" Z " + x);
}

async function main3() {
await main2();
await doSomething("---------");
}

console.log("----started----");
main3();
console.log("---------------");
</syntaxhighlight>

@@ แถว 82: / แถว 82: @@
+}
-function main2() {
+function main2alternative() {
    return (main()
              .then((x) => { return doSomething(" Z " + x); }));
+}
-async function main2alternative() {
+async function main2() {
    let x = await main();
    await doSomething(" Z " + x);

Js/async - ประวัติรุ่นแก้ไข

Jittat: /* Async / await */

Jittat: สร้างหน้าด้วย "== Code เริ่มต้น == function doSomething(msg) { let t = Math.random()*1500; setTimeout(() => {..."