How to get SharePoint User by User Id in JavaScript using JSOM

Solution

1. function getUserById() {
2.  
3.     var context = new SP.ClientContext.get_current();
4.     var user = context.get_web().get_siteUsers().getById('1073741823');//Give the user id here
5.     context.load(user);
6.     context.executeQueryAsync(
7.          Function.createDelegate(null, ensureUserSuccess),
8.          Function.createDelegate(null, onFail)
9.     );
10.  
11.     function ensureUserSuccess() {
12.         //You can access the properties here
13.         alert(user.get_title());
14.         alert(user.get_loginName());
15.     }
16.  
17.     function onFail() {
18.         alert('Fail');
19.     }
20. }