Class atributes not updating [node.js - express ]

Question

I have some troubles with a .js Object's atribute which is not updating when i ask it to.

I'm new in the javascript world, so i hope my issue won't be tricky.

First of all, this is a part of my Node class :

Node = function (label, vals, db, callback) {
    // attributes
    this.label = label;
    this.vals = vals;
    this.db = db;
    if (typeof calback == 'function') calback();
}
Node.prototype.insert_db = function (calback) {
    var vals = this.vals;
    // Create a node 
    console.log("1:"); // output print
    console.log(vals); // output print
    this.db.save(vals, function (err, node) {
        if (err) throw err;
        vals = node;
        console.log("2:"); // output print
        console.log(vals); // output print
    });
    this.vals = vals;
    console.log("3:"); // output print
    console.log(this.vals); // output print
    if (typeof calback == 'function') calback();
}

what i want to do with this code, is to update the "id" value of a my Node object after insertion. But... here is my console.log after runing this code :

var per = new Node('Whatever', { firstName: "aaaa", lastName: "aaaa", age: "aaaa" }, db2);
per.insert_db();

Console output :

1:
{ firstName: 'aaaa', lastName: 'aaaa', age: 'aaaa' }
3:
{ firstName: 'aaaa', lastName: 'aaaa', age: 'aaaa' }
2:
{ firstName: 'aaaa', lastName: 'aaaa', age: 'aaaa', id: 491 }

The 3rd state is (in second position) never get updated. I don't know where it comes from. I've spent the last 2 days on that problem, that i obviously can't handle anymore.

Thanks in advance.

EDIT Still having troubles. Thanks to @MarkHughes, here is my new code

Node.prototype.insert_db = function (callback) {
    var temp = this;
    this.db.save(this.vals, function (err, node) {
        if (err) throw err;
        temp.vals = node;
        console.log(temp.vals); // output print
        if (typeof callback == 'function') callback();
    });
}

Code ran by this one

var per = new Node('Person', { firstName: "aaaa", lastName: "aaaa", age: "aaaa" }, db2);
per.insert_db(res.render('login-index', { title: 'miam', dump: mf.dump(per) }));

Now here are the console.log(temp.vals)

{ firstName: 'aaaa', lastName: 'aaaa', age: 'aaaa', id: 515 }

And here is the rendered output (pre html) :

vals:  object(3): {
    firstName:  string(4): "aaaa"
    lastName:  string(4): "aaaa"
    age:  string(4): "aaaa"
}

The output is in the callback function wich is in the asynchronous function .save... And still no update. :(

I don't know if this helps, for debug only :

setTimeout(function() { console.log(temp) }, 3000);

written after the .save function returns this :

[...]
vals: { firstName: 'aaaa', lastName: 'aaaa', age: 'aaaa', id: 517 },
[...]

What am I doing wrong ?

Answer 1

.save is asynchronous, so you can't use the value returned by it outside its callback, hence moving the rest of your code inside the callback will fix it:

var t = this;
this.db.save(vals, function (err, node) {
    if (err) throw err;
    vals = node;
    console.log("2:"); // output print
    console.log(vals); // output print

    t.vals = vals;
    console.log("3:"); // output print
    console.log(t.vals); // output print
    if (typeof calback == 'function') calback();
});

Saving "this" into a variable allows access to it from inside the callback.

For your calling code, you need to ensure you are rendering the output in the callback from insert_db() - e.g. something like:

per.insert_db(function () { 
    res.render('login-index', { title: 'miam', dump: mf.dump(per) })
});

Note that you have to wrap res.render in a function() else what will be passed in as the callback will be the return value of executing that function, rather than the function itself.