javascript return promise

1function doSomething() {
2  return new Promise((resolve, reject) => {
3    console.log("It is done.");
4    // Succeed half of the time.
5    if (Math.random() > .5) {
6      resolve("SUCCESS")
7    } else {
8      reject("FAILURE")
9    }
10  })
11}
12
13const promise = doSomething(); 
14promise.then(successCallback, failureCallback);

1function myAsyncFunction(url) {
2  return new Promise((resolve, reject) => {
3    const xhr = new XMLHttpRequest();
4    xhr.open("GET", url);
5    xhr.onload = () => resolve(xhr.responseText);
6    xhr.onerror = () => reject(xhr.statusText);
7    xhr.send();
8  });
9}

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));