Prevent duplicate App scripts and styles from being loaded

[markhealey]

We are looking at adding a map to track App script and style dependencies so that multiple versions of the same files are not downloaded by a Container. This enhancement has been discussed in #129 and others primarily revolving around v2 conversations. @bentaber

[markhealey]

Proposing this for a new version 1.3.4.

[brianbaker]

Might consider solving #171 at the same time since its in the same code?

[markhealey]

Good call, thanks for linking the issues.

[bentaber]

I've only tested this in chrome, using the example container. Could use some help understanding how the jasmine tests are set up so I can try and add some for this.

[markhealey]

@bentaber I added one test to give you an idea of how they're setup. See here.

The Jasmine tests rely on F2.min.js in both the headless and regular browser tests, so be sure to run grunt js before grunt test. If you want to use the regular browser, run grunt test-live and open http://localhosts:8080/tests.

[markhealey]

After discussing the details of these changes, the F2 team sees them being released as a minor version change and not a patch. Therefore proposing version 1.4.0.

It's TBD whether this will get rolled into #142 or if #142 will become 1.5.0.

[markhealey]

Quick update for those watching. We've been rolling in a few commits over the past two weeks (all listed here) in the load-deps-once branch. Prior to the first revision on October 19, we'd been tracking numerous issues revolving around the subject of "dependency management" in certain browsers. Since then, the App dependency loader has been reviewed and significantly updated to address a number of issues including both #182 and #171. There are a couple of new unit tests to help validate the changes and an informal changelog follows.

• Prevent duplicate loading of AppManifest-defined styles and scripts Prevent duplicate App scripts and styles from being loaded #182
• Prevent scripts from loading and executing out of order in IE 8-9 App scripts can execute out of order in IE8 & 9 #171
• Added documentation in the spec around App life cycle, i.e., what happens when loading Apps
• Added new events and documentation for when an App's scripts have all been loaded (APP_SCRIPTS_LOADED)
• We are working through some continued testing in IE 8 before we call this good.

Finally, it is likely these updates (#184) will get merged into #142 for a final 1.4.0 release.

[markhealey]

If you want to test out this load-deps-once version, use this version of F2.js.