jQuery readies version 3.0 release candidate

The upcoming version of the JavaScript library will become the only fully supported edition upon release

jQuery readies version 3.0 release candidate

Attention Web developers: Get ready for what soon will be the only version of the jQuery JavaScript library available. Version 3.0 of the widely used library has moved to a release candidate stage. 

"When released, jQuery 3.0 will become the only version of jQuery," jQuery core lead Timmy Willison said. "The 1.12 and 2.2 branches will continue to receive critical support patches for a while but will not get any new features or major revisions." The upgrade will not support versions 6 through 8 of the Internet Explorer browser, he added.

Upgrading existing code should not be much of a problem, Willison explained. "Yes, there are a few 'breaking changes' that justified the major version bump, but we're hopeful the breakage doesn't actually affect that many people. To assist with upgrading, we have a brand-new 3.0 Upgrade Guide. And the jQuery Migrate 3.0-rc plugin will help you to identify compatibility issues in your code."

JQuery, which turned 10 years old January, is in use in 70.2 percent of the top 10 million websites, according to W3Techs, which surveys usage of Web technologies. Version 3.0 will include accommodations for ECMAScript 2015 Promises, used for deferred and asynchronous computations. JQuery.Deferred Objects are now compatible with Promises/A and ES2015 Promises, Willison said.

Some jQuery custom selectors will be sped up in the upgrade. "Thanks to some detective work by Paul Irish at Google, we identified some cases where we could skip a bunch of extra work when custom selectors like :visible are used many times in the same document," said Willison. "That particular case is up to 17 times faster now."

With the upgrade, animations use the requestAnimationFrame API on supportive platforms for smoother, less-CPU-intensive operations and more economical consumption of battery power. Also in version 3.0, error cases will not "silently fail," Willison said. "Perhaps in a profound moment you've wondered, 'What is the offset of a window?' Then you probably realized that is a crazy question -- how can a window even have an offset? In the past, jQuery has sometimes tried to make cases like this return something rather than having them throw errors. In this particular case of asking for the offset of a window, the answer up to now has been { top: 0, left: 0 } With jQuery 3.0, such cases will throw errors so that crazy requests aren't silently ignored."

This story, "jQuery readies version 3.0 release candidate" was originally published by InfoWorld.

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