v6.0.0

This major release is focused on massive improvements in speed, URL parsing, and error handling. The potential breaking changes are highlighted in bold below; the largest ones are around the jsdom.env error-handling paradigm.

This release also welcomes long-time contributer @Joris-van-der-Wel to the core team. You may recognize him from earlier changelogs. We're very happy to have his help in making jsdom awesome!

• io.js 2.0 onward is now required, as we have begun using ES2015 features only present there.
• Improved performance dramatically, by ~10000x in some cases, due to the following changes:
  • Overhauled the named properties tracker to not walk the entire tree, thus greatly speeding up the setting of id and name attributes (including during parsing).
  • Overhauled everything dealing with tree traversal to use a new library, symbol-tree, to turn many operations that were previously O(n^2) or O(n) into O(n) or O(1).
  • Sped up node.compareDocumentPosition and anything that used it (like node.contains) by doing more intelligent tree traversal instead of directly implementing the specced algorithm.
• Overhauled how error handling works in jsdom:
  • window.onerror (or window.addEventListener("error", ...)) now work, and will catch all script errors, similar to in browsers. This also introduces the ErrorEvent class, incidentally.
  • The virtual console is now the destination for several types of errors from jsdom, using the new event "jsdomError". This includes: errors loading external resources; script execution errors unhandled by window.onerror; and not-implemented warnings resulting from calling methods like window.alert which jsdom explicitly does not support.
  • Since script errors are now handled by window.onerror and the virtual console, they are no longer included in the initialization process. This results in two changes to jsdom.env and the initialization lifecycle:
    • The load(errors, window) callback was changed to onload(window), to reflect that it is now just sugar for setting a window.onload handler.
    • The done(errors, window) callback (i.e., the default callback for jsdom.env) has become done(error, window), and like every other io.js callback now simply gives you a single error object, instead of an array of them.
  • Nodes no longer have a nonstandard errors array, or a raise method used to put things in that array.
• URL parsing and resolution was entirely overhauled to follow the URL standard!
  • This fixes several long-standing bugs and hacks in the jsdom URL parser, which already had a mess of gross patches on top of the built-in io.js parser to be more web-compatible.
  • The new URL class has been added to window
  • The interfaces for HTMLAnchorElement.prototype and document.location (as well as URL, of course) are now uniformized to follow the URLUtils API (minus searchParams for now).
  • As part of this change, you may need to start passing in file: URLs to jsdom.env where previously you were able to get away with passing in filenames.
• Added the XMLHttpRequest.prototype.response getter.
• Fixed StyleSheetList.prototype.item to actually work. (@chad3814)
• Fixed the browser vm shim to properly add the built-in global properties (Object, Array, etc.) to the sandbox. If you were running jsdom inside a web worker and most of your scripts were broken, this should fix that.
• Fixed the hashchange event to correctly fire HashChangeEvent instances, with correct properties newURL and oldURL (instead of the incorrect newUrl and oldUrl used previously).
• Removed usage of the setimmediate library, as it required eval and thus did not work in CSP scenarios.

Finally, if you're a loyal jsdom fan whose made it this far into the changelog, I'd urge you to come join us in #1139, where we are brainstorming a modernized jsdom API that could get rid of many of the warts in the current one.