I'm trying to understand what asyncrounous programming is & from what I learned that the setTimeOut function is asyncrounous which mean that the next code will be executed and when the time elapses the code inside it will be executed , now I know that when I call the test function "second" will be printed first but I don't understand why "third" is printed before "first" , shouldn't it wait for the test function to be executed before it's printed.

function test(){
  setTimeout(() => {
    console.log("first")
  }, 1000);
  console.log("second")
}


test()
console.log("third")

CodePudding user response：

settimeout will execute the code after the amount of time you give pass which is 1 sec on your case

so anything else after it will run despite it in the same scope like in same function or even outside it

Settimeout

CodePudding user response：

well, no setTime is not a promise (don't get confused whit the promise object in js ) when u say i want it for a second from now you can't ever be sure it's depended on scheduling on event loop and how busy the current thread is

CodePudding user response：

So if what you're wanting is to have it wait to print out the result of the timeout before continuing to print "second" you need to do an async await model:

async function test(){

  await setTimeout(() => {
  
    console.log("first");
    
  }, 1000);
  
  console.log(second);
  
}

run();
console.log("third");

Note that the keyword async is necessary to mark a function as async. Then you must use the await keyword before an action that you want to wait for. I hop this helps.