Loading "knockout.mapping" plugin using require.js - asp.net-mvc-3

Question

I am creating an MVC3 application, with requireJS. In my views I need to convert the Model object into a knockout viewmodel object. So I need to use knockout and knockout.mapping libraries.
My application is designed in the following way,
1). All the script files are categorized into folders
Scripts/app/home/ - contains the scripts for the views in Home controller.
Scripts/lib/ - contains the scripts like jQuery, knockout,knockout.mapping, requirejs etc
2). In the "_Layout.cshtml" I am referencing "require.js" like this.
<script src="#Url.Content("~/Scripts/lib/require.js")" type="text/javascript"></script>
3). To configure the require.js settings I am using a different script file called "common.js" (Scripts/lib/common.js)
require.config(
{
baseUrl: "/Scripts/",
paths:{
jquery: "lib/jquery-2.0.3",
ko: "lib/knockout-2.3.0",
komapping: "lib/knockout.mapping"
}
});
4). This is my index.js file which is in 'Scripts/app/home/"
define(['ko', 'komapping'], function (ko, komapping) {
var person = function () {
var self = this;
self.getPersonViewModel = function (data) {
return ko.mapping.fromJS(data); ;
};
};
return { Person: person };
});
5). This is my "Index" action method in the "Home" controller
public ActionResult Index()
{
var person = new Person
{
Id = 1,
Name = "John",
Addresses = new List<Address>(new[]{new Address{Country = "Country 1", City = "City 1"}})
};
return View(person);
}
6). Finally this is my "Index" view
#model MMS.Web.Models.Person
<script type="text/javascript">
require(["/Scripts/common/common.js"], function () {
require(["app/home/index"], function (indexJS) {
var person = new indexJS.Person();
var vm = person.getPersonViewModel(#Html.Raw(Json.Encode(Model)));
});
});
</script>
The problem which I am facing is when loading the index.js file, I get a script error that the knockout.js cannot be loaded.
Failed to load resource: the server responded with a status of 404 (Not Found) - http:///Scripts/knockout.js
But if I remove the dependency of "komapping" inside the "index.js" file it loads correctly, but then I cannot use the mapping functionality.
I had a look inside these links, but couldn't find a solution,
Knockout.js mapping plugin with require.js and
https://github.com/SteveSanderson/knockout.mapping/issues/57
Your help, suggestions are much appreciated. Thanks!

Answer 1

I had the same issue. The problem is that the knockout.mapping defines a knockout dependency, so you need to satisfy this one when you load the script.
Here is how you should load your mapping stuff
require.config(
{
baseUrl: "/Scripts/",
paths:{
jquery: "lib/jquery-2.0.3",
knockout: "lib/knockout-2.3.0",
komapping: "lib/knockout.mapping"
},
shim: {
komapping: {
deps: ['knockout'],
exports: 'komapping'
}
}
});
Then in my case, I use an index.js file with a requirejs call like the following
requirejs(['jquery', 'knockout', 'komapping'], function($, ko, komapping){
ko.mapping = komapping;
//Do other stuff here
});