[GIS] Does the ArcGIS JavaScript API let me build / package the application using Dojo

arcgis-javascript-apiarcgis-serverdojo

I'm currently getting to grips with the new (3.1) ArcGIS JavaScript API and how it bundles Dojo and relies on Dojo's Asynchronous Module Definition (AMD) approach.

I'm familiar with AMD and recently completed a project using Require, Backbone, and OpenLayers in combination – overall a very pleasant experience.

However I'm worried by

how tightly-coupled Dojo is with the ArcGIS JavaScript API,
that trying to use Require instead of Dojo AMD throws an exception, and
that Dojo AMD doesn't seem to have the same user-base and momentum as Require, making it difficult to research / resolve problems without hitting the forums

My main concern is that I will write an ArcGIS JavaScript API application and not be able to build / package it into a single / small number of scripts. This will leave me with an application making 100+ HTTP requests at startup for all of the modules it depends on.

I've seen this article covering 3.0 but it doesn't mention the build process and I believe 3.0 is quite different. I've also seen this piece on building / packaging an application that uses the ArcGIS JavaScript API but the comments suggest this is pre-Dojo 1.7 AMD.

Have ESRI really only half implemented the AMD approach, and in a way that will actually make my application slower? Why can I not find ESRI documentation on building / packaging a JavaScript API-based application?

Any thoughts or experience here would be much appreciated.

EDIT Based on the answers so far it seems that no, ESRI hasn't provided any information on building your Dojo application after inflating the number of scripts involved. It seems the only useful information available is from non-official sources and slightly outdated (enough to cause problems). This leads to me wonder why more people aren't vocal about the API's new improvements / deficiencies

am I being too critical / demanding in expecting some more information here?
is no one using the latest version of the API?
should I use an older version of the API that doesn't depend on AMD?

Best Answer

Since esri does not ship source code you cannot build one layer package with all your classes. You will have to push out the esri api locally or using the CDN and then pull down your layer file. So you will have 2 and then the extra's that esri forgot to bundle or chose not to.

We've put together a discard layer so that you don't duplicate packages within your own built layer file and the esri layer file. This is pre AMD but as you've noticed, AMD is only partially implemented in the current version of the API.

This blog post will outline everything you need to know and the concept will apply for newer versions.

the freenode irc chatroom #dojo has great realtime information if you dont' want to wait around for the forum.

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ArcGIS Server – Best Frameworks for Robust Application Implementation Using ArcGIS Server JS API

I would agree with Moyles that the samples are just samples and dojo boileplate is a great resource however at current snovers boilerplate isn't a viable solution. You have two different versions of dojo going on there. The current js api still uses the classic require syntax of dojo 1.6.1 and does not support AMD. I'm sure that a newer js api will be built on 1.7.x and since converting classic dojo.defined modules to AMD is mostly trivial I would choose that route.

If you're starting your project now then I would choose whatever server side framework you wanted to use (if it is necessary for your application. If its just a single page viewer with no server side requirements then don't over complicate things). It could be rails, php, asp, whatever. Follow the best practices for your framework/language.

Then since esri is built on dojo you are already loading a great js framework for creating large scale web applications. Structure your code so that the dojo's loader can load your widgets and modules with the dojo require syntax. Write dojo widgets and modules, use dijits and dojox tools when necessary ( http://dojotoolkit.org/documentation/tutorials/1.6/declare, http://dojotoolkit.org/documentation/tutorials/1.6/recipes/custom_widget/, http://dojotoolkit.org/documentation/tutorials/1.6/understanding_widget, http://dojotoolkit.org/documentation/tutorials/1.6/templated, http://dojotoolkit.org/documentation/tutorials/1.6/cdn). Do not write inline js like the samples do. Create a build profile to optimize all your code when its time for production.

You have to keep your esri and custom code separate to a certain degree because they don't offer the source for compiling - it's already built and minified. The build tool doesn't like that so much.

EDIT

I built a grunt tool, esri_slurp to download the esri js api so you can use it as a package in your applications. This allows you to run the build and get a single file.

[GIS] Loading custom dojo and Esri

To load your custom UI tools along with ESRI's version of Dojo, you'll need to add the name and location of your custom package to the dojoConfig object in the script. Just before you load ESRI's JavaScript API in the head of document, set your dojoConfig similar to the following

<script type="text/javascript">
  dojoConfig = {
    async: true,
    packages: [
      {
        name: "customUI",
        location: "/js/customUI" // or wherever you keep your custom code
      }
    ]
  };
</script>
<script src="http://js.arcgis.com/3.6/"></script>

Then, later, you can call it in a require or define statement.

require(["customUI/DrawingTool", "esri/map", "dojo/ready"],
  function (DrawingTool, Map, ready) {
    ready(function () {
       var map = new Map("mapdiv", {});
       var myDrawingTool = new DrawingTool({ map: map});
       // do whatever with it.
    });
  }
);

Here's some reading to help you set it up properly:

Best Answer

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ArcGIS Server – Best Frameworks for Robust Application Implementation Using ArcGIS Server JS API

EDIT

[GIS] Loading custom dojo and Esri

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