Thorsten Behrens, one of the leaders of the LibreOffice graphics subsystem development team, published a demo version of the LibreOffice office suite compiled into WebAssembly intermediate code and capable of running in a web browser (about 300 MB of data is downloaded to the user's system). The Emscripten compiler is used to convert to WebAssembly, and the VCL backend (Visual Class Library) based on the modified Qt5 framework is used to organize the output. WebAssembly-specific fixes are being developed in the main LibreOffice repository.
Unlike the LibreOffice Online edition, the assembly based on WebAssembly allows you to run the entire office suite in the browser, i.e. all code runs on the client side, while LibreOffice Online runs and processes all user actions on the server, and only the interface is translated to the client browser. The removal of the main part of LibreOffice to the browser side will allow creating a cloud-based edition for collaboration, removing the load from servers, minimizing differences from the desktop LibreOffice, simplifying scaling, able to work offline, and also allowing the organization of P2P interaction between users and end-to-end encryption of data on user side. The plans also include the creation of a widget based on LibreOffice to integrate a full-fledged text editor into pages.
Source: opennet.ru