What’s New in SpreadJS v19.1

Pittsburgh, PA – May 19^th, 2026 MESCIUS USA, Inc., a global provider of award-winning enterprise software development tools, is pleased to announce the SpreadJS v19.1 release. The highlights of SpreadJS v19.1 include a new XLSX Editor for Visual Studio Code, enhancements to the optional GanttSheet add-on component, and support for running custom functions directly in the Calc Worker. SpreadJS v19.1 is now available for existing customers as an upgrade and for new customers as a download on the MESCIUS website.

The new SpreadJS Designer VS Code plugin brings full spreadsheet design capabilities directly into your editor, letting you open, edit, and save Excel, .csv, and more file types without leaving Visual Studio Code. It adds an “Open with SpreadJS” context-menu action, handles password‑protected Excel files with inline prompts, and integrates with Visual Studio Code’s save flow and command palette for creating new files. The plugin is tailored for the Visual Studio Code environment with a customized file menu, support for classic/toolbar ribbon modes, automatic light/dark theme adaptation, and localization via language and culture settings. Read the release announcement to learn more about the new Designer VS Code plugin and how to install the extension.

In the v19.1 release, the SpreadJS Designer now includes an enhanced GanttSheet panel that centralizes field mapping, hierarchy configuration, and default task mode into a single, drag‑and‑drop experience—complete with auto-mapping and intelligent inference based on your data schema. This makes it far easier to bind data sources and use GanttSheet for both scheduling and general timeline/date‑range visualizations without hunting through multiple dialogs. Additionally, GanttSheet now fully honors SpreadJS TableTheme styling across its table, time scale, and chart regions, so fonts, colors, backgrounds, alternating rows, and gridlines stay visually consistent with your TableSheet designs. Visit the website to learn more about the new GanttSheet enhancements in SpreadJS’s latest release.

SpreadJS now supports running custom functions directly in the Calc Worker, enabling calculations to execute off the main UI thread for smoother, more responsive spreadsheet applications. In our benchmarks, this improved performance by up to 3 times faster. For developers building data-heavy web applications, financial tools, planning systems, or spreadsheet-based workflows, this means users can continue interacting with the application. At the same time, complex calculations run in the background. Learn more about using custom functions in Calc Worker in SpreadJS v19.1.

"We are excited to release SpreadJS 19.1, which brings faster formulas with Calc Worker, deeper capabilities with What-If Analysis, and a true Excel-like editing experience in VSCode," said Product Manager Chris Bannon.

About MESCIUS USA, Inc.: MESCIUS USA, Inc. is one of the world's largest providers of developer components. The company employs 400 people and serves hundreds of thousands of customers worldwide. MESCIUS is committed to providing enterprises around the world with state-of-the-art developer tools and components, software services, and solutions. For more information, visit https://developer.mescius.com.

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