New Feature in Excel Supports Custom JavaScript Functions

Good news, JavaScript fans: This week, Microsoft announced that it was adding support for custom JavaScript functions in Excel.

What does this mean?

It means that Microsoft Excel will be even more powerful than it is now.

Excel users will be able to create custom Excel formulas using JavaScript code that will appear in Excel’s default formula database. Users can then use these codes in spreadsheets.

The user-defined JavaScript functions allow developers to import information from websites, like bank account balances, and to stream live data. You can read more about it here.

Why is this good news?

While Excel already allows the writing of complex scripts using VBA, using JavaScript provides a number of advantages. The extremely popular JavaScript easily connects to third-party services and can run on any platform.

Is this announcement surprising?

Not at all. Microsoft has been in favor of adding JavaScript support for Office developers for some time, with the goal of providing developers the ability to build powerful solutions within spreadsheets. In September 2017, it introduced Excel JavaScript application programming interfaces and said that the functionality would continue to expand.

What are the downsides?

Security experts have already raised concerns about the potential for JavaScript to be abused by malicious developers to run unauthorized code on users’ computers.

On another note, writing JavaScript functions is far more complicated than writing in VBA. It demands knowledge of JSON, XML and possibly even the difference between synchronous and asynchronous functions.

“A new generation of web developers will find writing in JavaScript relatively easy,” noted Dany Hoter, Datarails solutions architect and Excel expert, “while the Excel power user will feel totally excluded from the party.”

What other features were announced?

Microsoft announced that Excel will soon also support Microsoft Azure Machine Learning services, as well as Custom Visuals for Power BI.

When will this be available?

Right now, JavaScript custom functions for Excel is available in Developer Preview to Office 365 subscribers who are part of the Office Insiders program. Azure Machine Learning functions and Power BI Custom Visuals will be coming soon.