jQuery 4.0 has marked a significant milestone as the first major update in nearly ten years, enhancing its features while streamlining its functionality for modern web development. This release notably drops support for Internet Explorer 10 and other legacy browsers, reflecting a trend in web development towards leveraging improved browser compatibility and robust native JavaScript capabilities.
The update introduces ES modules and utilizes Rollup for efficient bundling, effectively reducing the library size by over 3KB. This was achieved by eliminating outdated compatibility hacks and APIs that are now natively supported by modern browsers. For example, the release aligns with W3C focus and blur event specifications and supports Trusted Types to enhance security against cross-site scripting (XSS) attacks.
Despite these advancements, some within the developer community express skepticism about jQuery’s relevance, given the powerful capabilities of modern JavaScript. However, many developers continue to appreciate jQuery for its straightforward API and ease of use, particularly for rapid development and handling complex tasks with concise code.
An interesting component of the release is an explanation regarding JavaScript string reversal, especially concerning emoji characters. When reversing strings, the <code>split()</code> method can misinterpret characters because it processes strings as 16-bit units rather than considering entire characters, especially those formed by surrogate pairs. The documentation suggests using <code>Array.from()</code> or spread operators as a solution to handle these multi-byte characters correctly, ensuring precise string manipulation.
Overall, jQuery 4.0 reflects an important evolution in the library’s lifecycle, adapting to modern web development needs while maintaining its core simplicity and functionality.

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jQuery 4.0 is the first major update in nearly a decade, dropping support for Internet Explorer 10 and legacy browsers while introducing ES modules and Rollup bundling. The library size decreased by over 3KB through removal of outdated compatibility code. Key improvements include alignment with W3C event specifications and Trusted Types support for XSS protection. The release addresses JavaScript string reversal challenges with emoji characters, recommending Array.from() or spread operators over split() for proper handling of surrogate pairs.

Understanding jQuery 4.0: Major Update and Its Implications