Mongorito: save(...).then is not a function - node.js

Question

I tried something similar to the example given on the readme.md file:
var Mongorito = require('mongorito');
var Model = Mongorito.Model;
Mongorito.connect('mongodb://localhost:27017/cr-test');
class User extends Model {
collection() {
return 'users';
}
}
var user1 = new User({
name: "James Gosling",
email: "user1#gmail.com",
password: "changeme"
});
user1.save().then(() => {
console.log('User Created');
});
when I run node --harmony server.js I get this error:
user1.save().then(() => {
^
TypeError: user1.save(...).then is not a function
at Object.<anonymous> (...\app\server.js:24:14)
at Module._compile (module.js:398:26)
at Object.Module._extensions..js (module.js:405:10)
at Module.load (module.js:344:32)
at Function.Module._load (module.js:301:12)
at Function.Module.runMain (module.js:430:10)
at startup (node.js:141:18)
at node.js:980:3
Could someone explain me how could I fix that?

Answer 1

The readme on GitHub is outdated, the project's website now states:
MongoDB ODM for Node.js based on ES6 generators.
No callbacks or promises.
It uses generators, which can find an example of on the getting started page:
'use strict';
function* saveUser () {
var user1 = new User({
name: "James Gosling",
email: "user1#gmail.com",
password: "changeme"
});
yield user1.save();
}
In order for generators to work, you must use 'use strict;' and the function* syntax. This GitHub project has additional examples.
Also, starting with Node v4, you no longer need the --harmony (now a synonym of --es_staging) flag for generators.

Answer 2

or you can do like this also ... but here you can execute just a single statement
user1.save().then(savedUser => console.log(`saved user: ${savedUser}`));