async await examples

async-consumer-with-await.js

async function callerFunction123(){
  var result = await fnName123();
  console.log( result );//will print "value_123"
}

async-fn-signature.js

async function fnName123(){/*code here*/}

async-fn.js

async function fnName123() {
    return new Promise((resolve, reject) => {
      //either call resolve for success response with the result -> 
      resolve("value_123");
      //or call reject for error response with the error info -> 
      reject(new Error("error reason");
    });
}

settimeout-async.js

//setTimeout wrapper as async function.
async function setTimeoutAsync(fn, ms) {
  return new Promise((resolve, reject) => {

    setTimeout(() => {
      try {
        var result = fn();
        resolve(result);
      } catch (err) {
        reject(err);
      }
    }, ms);

  });
}

//user code that uses sleep function
async function userCode() {
  //do something
  console.log("1");
  
  //invoke a function after every 1s 3 times.
  for (var i = 0; i < 3; i++) {
    var result = await setTimeoutAsync(() => { return "value123=" + i; }, 1000);
    console.log(i + "->" + result);
  }

  //do something more
  console.log("2");
}

userCode();//run it for testing.

sleep.js

//sleep function as async function using setTimeout internally.
async function sleep(ms){
    return new Promise((resolve, reject) => {
      setTimeout(resolve, ms);//resolve is called after ms milliseconds.
    });
}

//user code that uses sleep function
async function userCode(){
  //do something
  
  //sleep for 100ms
  await sleep(100);
  
  //do something more
}

userCode();//run it for testing.