jsdom

• Fixed getComputedStyle() with calc() and other functions throwing an exception, which regressed in v30.0.0. (@asamuzaK)
• Sped up up range operations on large documents (@leonidaz)

Breaking changes:

• Node.js minimum version raised to ^22.22.2 || ^24.15.0 || >=26.0.0.

Other changes:

• Added CSS.escape() and CSS.supports() functions. (@asamuzaK)
• Added 'background-position-x' and 'background-position-y' CSS properties. (@olagokemills)
• Fixed getComputedStyle() to convert length values into pixels. (@asamuzaK)
• Fixed CSS function serialization, e.g., in the return value of getPropertyValue(). (@asamuzaK)
• Fixed the type of error thrown by document.evaluate() (@dokson)

• Fixed 'border-radius' computed style serialization. (@asamuzaK)
• Fixed computed style computation when using 'background-origin' and 'background-clip' CSS properties. (@asamuzaK)
• Significantly optimized initial calls to getComputedStyle(), before the cache warms up. (@asamuzaK)

• Added basic support for the ratio CSS type. (@asamuzaK)
• Fixed getComputedStyle() sometimes returning outdated results after CSS was modified. (@asamuzaK)

• Significantly improved and sped up getComputedStyle(). Computed value rules are now applied across a broader set of properties, and include fixes related to inheritance, defaulting keywords, custom properties, and color-related values such as currentcolor and system colors. (@asamuzaK)
• Fixed CSS 'background' and 'border' shorthand parsing. (@asamuzaK)

• Fixed CSS parsing of 'border', 'background', and their sub-shorthands containing keywords or var(). (@asamuzaK)
• Fixed getComputedStyle() to return a more functional CSSStyleDeclaration object, including indexed access support, which regressed in v29.0.0.

• Added TextEncoder and TextDecoder.
• Improved decoding of HTML bytes by using the new @exodus/bytes package; it is now much more correct. (@ChALkeR)
• Improved decoding of XML bytes to use UTF-8 more often, instead of sniffing for <meta charset> or using the parent frame's encoding.
• Fixed a memory leak when Ranges were used and then the elements referred to by those ranges were removed.

Breaking changes:

• Node.js v22.13.0+ is now the minimum supported v22 version (was v22.12.0+).

Other changes:

• Overhauled the CSSOM implementation, replacing the @acemir/cssom and cssstyle dependencies with fresh internal implementations built on webidl2js wrappers and the css-tree parser. Serialization, parsing, and API behavior is improved in various ways, especially around edge cases.
• Added CSSCounterStyleRule and CSSNamespaceRule to jsdom Windows.
• Added cssMediaRule.matches and cssSupportsRule.matches getters.
• Added proper media query parsing in MediaList, using css-tree instead of naive comma-splitting. Invalid queries become "not all" per spec.
• Added cssKeyframeRule.keyText getter/setter validation.
• Added cssStyleRule.selectorText setter validation: invalid selectors are now rejected.
• Added styleSheet.ownerNode, styleSheet.href, and styleSheet.title.
• Added bad port blocking per the fetch specification, preventing fetches to commonly-abused ports.
• Improved Document initialization performance by lazily initializing the CSS selector engine, avoiding ~0.5 ms of overhead per Document. (@thypon)
• Fixed a memory leak when stylesheets were removed from the document.
• Fixed CSSStyleDeclaration modifications to properly trigger custom element reactions.
• Fixed nested @media rule parsing.
• Fixed CSSStyleSheet's "disallow modification" flag not being checked in all mutation methods.
• Fixed XMLHttpRequest's response getter returning parsed JSON during the LOADING state instead of null.
• Fixed getComputedStyle() crashing in XHTML documents when stylesheets contained at-rules such as @page or @font-face.
• Fixed a potential hang in synchronous XMLHttpRequest caused by a race condition with the worker thread's idle timeout.

• Added blob.text(), blob.arrayBuffer(), and blob.bytes() methods.
• Improved getComputedStyle() to account for CSS specificity when multiple rules apply. (@asamuzaK)
• Improved synchronous XMLHttpRequest performance by using a persistent worker thread, avoiding ~400ms of setup overhead on every synchronous request after the first one.
• Improved performance of node.getRootNode(), node.isConnected, and event.dispatchEvent() by caching the root node of document-connected trees.
• Fixed getComputedStyle() to correctly handle !important priority. (@asamuzaK)
• Fixed document.getElementById() to return the first element in tree order when multiple elements share the same ID.
• Fixed <svg> elements to no longer incorrectly proxy event handlers to the Window.
• Fixed FileReader event timing and fileReader.result state to more closely follow the spec.
• Fixed a potential hang when synchronous XMLHttpRequest encountered dispatch errors.
• Fixed compatibility with environments where Node.js's built-in fetch() has been used before importing jsdom, by working around undici v6/v7 incompatibilities.

• Overhauled resource loading customization. See the new README for details on the new API.
• Added MIME type sniffing to <iframe> and <frame> loads.
• Regression: WebSockets are no longer correctly throttled to one connection per origin. This is a result of the bug at nodejs/undici#4743.
• Fixed decoding of the query components of <a> and <area> elements in non-UTF-8 documents.
• Fixed XMLHttpRequest fetches and WebSocket upgrade requests to be interceptable by the new customizable resource loading. (Except synchronous XMLHttpRequests.)
• Fixed the referrer of a document to be set correctly when redirects are involved; it is now the initiating page, not the last hop in the redirect chain.
• Fixed correctness bugs when passing ArrayBuffers or typed arrays to various APIs, where they would not correctly snapshot the data.
• Fixed require("url").parse() deprecation warning when using WebSockets.
• Fixed <iframe>, <frame>, and <img> (when canvas is installed) to fire load events, not error events, on non-OK HTTP responses.
• Fixed many small issues in XMLHttpRequest.