Blog

Ext JS 4.1 Update

October 10, 2011 | Michael Mullany

In August, we did a preview blog on Ext JS 4.1. In it, we explained that we were going to concentrate on Performance and Documentation for our release. We also said that we expected to ship it in “mid-to-late September”. To our disappointment, we haven’t been able to make that date, and now I wanted to update you on our new product delivery schedule.

Update: Ext JS 4.0.7 is now available Download Ext JS 4.0.7

The Challenge: Ext JS 4.0 Performance in IE7/8

Our goal for Ext JS 4.1 is to meaningfully accelerate performance on older IE browsers. Compared to IE9, Chrome and other modern browsers, IE 7 and IE8 have slow JavaScript engines and DOM interactions. Ext JS 4.0 exercises these functions particularly hard. As a result while Ext JS 4 performance is solid on modern browsers, its page display time for complex layouts is quite slow in IE7 and IE8.

Optimization Sources for IE

The Ext JS 4.1 release is focused on speeding up page display time in IE7/8. Based on initial performance profiling, we ascertained that moving from incremental rendering to batch rendering would greatly speed up page display time. We initially scoped this as a two month project. However, moving to batched rendering proved to be only half the battle. We subsequently uncovered another set of performance bottlenecks in post-rendering in IE7/8 which has taken us time to re-engineer. As a result, while we’re finally code-complete on the core refactoring, we now need stabilization and beta time. Because of this, we now expect to see a beta of 4.1 at the end of October, which we anticipate will deliver a significant speed-up in complex layouts. (Due to the similarity of IE6 with IE7/8, IE6 performance will also improve significantly). We have good confidence in our ability to hit this new date – although unexpected issues may still arise.

Releasing 4.0.7 to General Community

We’re disappointed about not being able to bring you 4.1 in the time frame we promised. As a result, we will be making our 4.0.7 release – normally only available to commercial support subscribers – available to the entire community in the next week. 4.0.7 contains almost two hundred bug releases subsequent to 4.0.2a, and we want you to have them on an accelerated time-table.

We’ll be making periodic progress reports on 4.1 on the forums as we approach final release, and providing performance workarounds in the short-term for those of you who can’t wait for 4.1 to release.

Performance Data from Complex Layouts

If you are currently encountering performance problems with your Ext JS 4.0 app on IE7/8, we’re also making a performance profiler available with instructions on how to send us performance data. We’ve identified additional areas we want to optimize for 4.2, and we’d like to gather more test data from as many applications with complex layouts as possible.

Changing How We Communicate Release Dates and Status

As we look over our ability to predict release dates, we just haven’t done a good job at this in 2011. Ext JS 4 was later than we originally announced, and our other releases have slipped past their initial launch targets. While I could take refuge in the statement “software is hard and unpredictable”, I don’t think excuses are much use to you when you have projects with hard dependencies on our ability to deliver on time. Apologies.

As a result, starting today, we’re going to be more conservative about communicating dates and we will be careful to communicate our level of confidence in those dates. In addition, we want to start providing more detail on what we’re working on and what we’re not. Using blog posts and forum posts seems to be insufficient. So, we’re looking at better ways of sharing what we’re doing with you on a continuous and transparent basis, including potentially providing open read-only access to our bug tracker.

We’re committed to Ext JS as the best application framework for desktop applications, and we hope that you’ll be pleased with our work in Ext JS 4.1.