requirejs/example-multipage-shim

requirejs/example-multipage-shim

This project shows how to set up a multi-page requirejs-based project that has the following goals:

• Each page uses a mix of common and page-specific modules.
• All pages share the same requirejs config.
• After an optimization build, the common items should be in a shared common layer, and the page-specific modules should be in a page-specific layer.
• The HTML page should not have to be changed after doing the build.
• shim config is used to load Backbone and underscore.

This project is different from the standard requirejs/example-multipage because shim config is used. Shimmed modules need their dependencies loaded before they are executed. It is not as robust as normal modules. Additionally, the common.js file has shim config in it. See the js/app/main1.js file for the Backbone and underscore use.

The shim config requires shimmed dependencies to be loaded first, before the shimmed script is executed. So instead of using data-main="js/page1" approach as used in example-multipage, this example inlines the requirejs calls in the HTML for the page.

If data-main was used instead, then there would need to be a 'js/page1' that would contain the <script> contents in page1.html, but that js/page1.js could not be the target of the optimization step, since it would inline the 'app/main1' dependencies above the requirejs() call for 'js/common'. If 'js/page1' used a shimmed script, but the shim dependency was in 'js/common', then the shimmed code would execute before the common layer that contains the shim dependency loads.

Since 'js/page1' cannot have any other modules inlined in its built version, it would add an extra HTTP request to use the 'js/page1' approach. By inlining that code in the HTML file, that extra HTTP request is avoided. If shim config is not needed, then the setup is simpler, see requirejs/example-multipage.

Getting this project template

If you are using volo:

volo create projectname requirejs/example-multipage-shim

Otherwise, download latest zipball of master.

Project layout

This project has the following layout:

• tools: The requirejs optimizer, r.js, and the optimizer config, build.js.
• www: The code that runs in the browser while in development mode.
• www-built: Generated after an optimizer build. Contains the built code that can be deployed to the live site.

This www has the following layout:

• page1.html: page 1 of the app.
• page2.html: page 2 of the app.
• js
  • app: the directory to store app-specific modules.
  • lib: the directory to hold third party modules, like jQuery.
  • common.js: contains the requirejs config, and it will be the build target for the set of common modules.

To optimize, run:

node tools/r.js -o tools/build.js

That build command creates an optimized version of the project in a www-built directory. The js/common.js file will contain all the common modules. js/app/main1.js will contain the main1-specific modules, js/app/main2.js will contain the main2-specific modules.

This means that for page 1, after an optimization, there will be two scripts loaded:

• js/common.js
• js/app/main1.js

Building up the common layer

As you do builds and see in the build output that each page is including the same module, add it to common's "include" array in tools/build.js.

It is better to add these common modules to the tools/build.js config instead of doing a requirejs([]) call for them in js/common.js. Modules that are not explicitly required at runtime are not executed when added to common.js via the include build option. So by using tools/build.js, you can include common modules that may be in 2-3 pages but not all pages. For pages that do not need a particular common module, it will not be executed. If you put in a requirejs() call for it in js/common.js, then it will always be executed.

More info

For more information on the optimizer: http://requirejs.org/docs/optimization.html

For more information on using requirejs: http://requirejs.org/docs/api.html