1var promise = new Promise(function(resolve, reject) {
2  // do some long running async thing…
3  
4  if (/* everything turned out fine */) {
5    resolve("Stuff worked!");
6  }
7  else {
8    reject(Error("It broke"));
9  }
10});
11
12//usage
13promise.then(
14  function(result) { /* handle a successful result */ },
15  function(error) { /* handle an error */ }
16);

1let promise = new Promise(function(resolve, reject){
2  try{
3  	resolve("works"); //if works
4  } catch(err){
5    reject(err); //doesn't work
6  }
7}).then(alert, console.log); // if doesn't work, then console.log it, if it does, then alert "works"

1/*
2Promise is a constructor function, so you need to use the new keyword to 
3create one. It takes a function, as its argument, with two parameters - 
4resolve and reject. These are methods used to determine the outcome of the
5promise. 
6The syntax looks like this:
7*/
8
9const myPromise = new Promise((resolve, reject) => {
10
11});
12
13

1const promiseA = new Promise( (resolutionFunc,rejectionFunc) => {
2    resolutionFunc(777);
3});
4// At this point, "promiseA" is already settled.
5promiseA.then( (val) => console.log("asynchronous logging has val:",val) );
6console.log("immediate logging");
7
8// produces output in this order:
9// immediate logging
10// asynchronous logging has val: 777
11

1myPromise.then(
2  function(value) { /* code if successful */ },
3  function(error) { /* code if some error */ }
4);

1var posts = [
2  {name:"Mark42",message:"Nice to meet you"},
3  {name:"Veronica",message:"I'm everywhere"}
4];
5
6function Create_Post(){
7  setTimeout(() => {
8    posts.forEach((item) => {
9      console.log(`${item.name} --- ${item.message}`);
10    });
11  },1000);
12}
13
14function New_Post(add_new_data){
15  return new Promise((resolve, reject) => {
16    setTimeout(() => {
17     posts.push(add_new_data);
18      var error = false;
19      if(error){
20        reject("Something wrong in </>, Try setting me TRUE and check in console");
21      }
22      else{
23        resolve();
24      }
25    },2000);
26  })
27}
28
29New_Post({name:"War Machine",message:"I'm here to protect"})
30    .then(Create_Post)
31    .catch(err => console.log(err));