No, Microsoft is not rewriting Office in Javascript

A tweet by a Microsoft developer has caused a bit of hubbub today after it implied Microsoft was rewriting all of their Office Suite in Javascript.

Sean Larkin, Technical Program Manager for Microsoft Web Platform, wrote:

(Ive never been able to say this yet)
?Well Actually!?

All of Office 365 is (almost finished) being completely rewritten in this little scripting language called #JavaScript.

And Skype
And Microsoft Teams
And @Code
And all of @MSEdgeDev Debug Protocol (instead of C++)

nbd https://t.co/WFahDhap6K

— ???????Sean Larkin (@TheLarkInn) June 13, 2018

This understandably caused a lot of concern regarding performance and the possibility of losing features due to using a less powerful language.

Of course, Windows users are already used to Javascript applications like Microsoft Teams and Slack, which are Electron Apps, and Skype is expected to be soon rewritten in React Native.  On the other hand, Teams is not the most performant app, and Office is already resource-hungry, and a Javascript version will likely be 10 times more so.

Fortunately, Windows users need not worry, as Larkin clarified in a post on Reddit.

Hi there!!! Original Tweeter here! I’m Sean and I’m a Program Manager at Microsoft working on Microsoft Edge and Edge Dev Tools!

Going to clarify across a few things. Some was lack of more then 280 chars in a tweet and not expecting this to get beyond #JavaScript twitter.

1. MS Teams, VS Code, is already written _with_ TypeScript which is compiled to JavaScript powered by Electron. It is an electron application. VS Code is on GitHub and Open Source if you’d like to see examples of how or what.

2. We are not abandoning C++, C#, or any of the other awesome languages, apis, and toolings that we use across Microsoft. EdgeHTML is almost entirely written in C++ like any other browser engine. However we do also run JavaScript (compiled from TypeScript) in DevTools, and leverage open source technologies like React and webpack to build the UI’s for them.

3. Office 365’s UI, a lot of it, but definitely not all of it, are pieces that are built using React Native (Windows). API’s and Services are still going to be powered by C++, C#, or whatever is the most appropriate for that team. Nothing is converting to “all/completely” JavaScript/TypeScript.

4. React Native compiling JavaScript to “native code” is arguably wrong. Most of what is native are API’s interactions and Native Modules that can be communicated with through JavaScript. WebViews power UI rendering thanks to React. Thanks to the Skype Engineer who sniped me on that in discussion .

5. Feel free to ask anything else! It’s the least I can do for tweeting some pretty unclear messaging.  ?

While Word may never be rewritten in Javascript, it does, however, appear to be the future of most new applications or ones which need to be rewritten from scratch, in our increasingly cross-platform world.

Thanks, Vladimir for the tip.