Can someone explain pls why the Promise returns pending in the first function, but resolved in the other two? When i read MDN it states that just using the word async wont make the code inside asynchronous (we need to use the word await as well). Also, I return the promise explicitly, since I use resolve() (which should return fulfilled promise as in two other functions, yet it returns Pending in the first function). I provided the code below.
const testFunc = async() => {
return new Promise((resolve,reject)=> {
resolve()
})
}
const testFunc2 = () => {
return new Promise((resolve,reject)=> {
resolve()
})
}
const testFunc3 = () => {
return new Promise((resolve,reject)=> {
resolve()
})
}
testFunc().then(()=> console.log("Hello")).then(()=> console.log("there")).then(()=> console.log("Obi One"))
testFunc2().then(()=> console.log(1)).then(()=> console.log(2)).then(()=> console.log(3))
testFunc3().then(()=> console.log(4)).then(()=> console.log(5)).then(()=> console.log(6))
console.log(testFunc())
console.log(testFunc2())
console.log(testFunc3())
// Results in the console:
// Promise {<pending>}
// Promise {<fulfilled>: undefined}
// Promise {<fulfilled>: undefined}
// 1
// 4
// 2
// 5
// Hello
// 3
// 6
// thereThats because testFunc (the function with async keyword) is equalevent to this:
const testFunc = () => {
return new Promise((resolve,reject)=> {
resolve(new Promise((r) => {
r()
}))
})
}
and not
const testFunc = () => {
return new Promise((resolve,reject)=> {
resolve()
})
}
Using async queues the executer as a microtask.
Read about it here: https://whistlr.info/2021/async-and-tasks/
The key point:
When you write an asynchronous function, you force the caller to use a microtask to read its result. This is the case even if you don't await inside it—it will return a Promise regardless