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PhantomJS 2 and JavaScript Goodies

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As I mentioned in my earlier blog post, we are now working torward stabilizing the development version of PhantomJS. One thing I would like to elaborate here with respect to the features of this forthcoming PhantomJS 2 is its improved JavaScript support.

With the fresher WebKit (thanks to Qt 5.3’s QtWebKit module), PhantomJS 2 also benefits from a lot of JavaScript improvement in JavaScriptCore, the JavaScript engine of WebKit. This brings PhantomJS to the more-or-less expectation of features which are supposed to be supported by a modern web browser.

test262

In fact, if we run the official test suite for ECMA-262, the ECMAScript Language Specification version 5.1, at test262.ecmascript.org, then we will see that PhantomJS (just like Safari 7) only fails 2 tests. If you compare it with other browsers, Chrome 36 has 4 failures and Firefox 31 has 42 failing tests. In a way, we can say that (by leveraging JavaScriptCore), PhantomJS is pretty much as standard compliant as it could get.

failures

Among others, many will rejoice for the availability of Function.prototype.bind (bug 10522), something that is missing from the old QtWebKit in Qt 4.8. There were various attempts to solve this in the past, see my previous post to the mailing-list. However, as I wrote there, sometimes our collective effort was not enough to move the mountain.

Another related improvement is the handling of the special object arguments. Just like other modern browsers, now you can JSON.stringify this object (bug 11845), use in a for-in loop (bug 11558, bug 10315), and call Object.keys on it (bug 11746).

PhantomJS 2 will be released whenever it is ready (monitor the mailing-list if you want to get notified). Meanwhile, if you want to compile it yourself and play with this bleeding-edge version, follow the step-by-step instructions. If you are on Linux or OS X (like typical geeks these days), building it yourself should take just 30 minutes on a fairly decent machine.

Good things come to those who wait!

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