I noticed today that all of our SPFx solutions were throwing a compiler error within Visual Studio Code. Apparently the dataVersion getter included in the boilerplate of Yeoman scaffolded projects is suddenly incompatible.

Here’s the code:

  protected get dataVersion(): Version {
    return Version.parse('1.0');

Here’s the error:

'dataVersion' is defined as a property in class 'BaseClientSideWebPart<[IMyWebPart]>', but is overridden here in 'MyWebPart' as an accessor.

TypeScript update breaks SPFx dataVersion - error message

I did a quick Google search, but didn’t find anything specific to the Framework. Why would I expect to? These were (literally) working on Friday when I left.

That got me thinking… TypeScript version

Sure enough.

TypeScript update breaks SPFx dataVersion - TypeScript version

Thankfully this is very easy to resolve. But why did it happen? My Visual Studio Code instance updated when I started it this morning, and it appears to have installed the latest version of TypeScript along with it. We all know that this is less than ideal with SharePoint/SPFx development.

Let’s get to fixing it.

Within Visual Studio Code; press [F1] -> type “TypeScript” -> select “TypeScript: Select TypeScript version…”

Now, select “Use Workspace version x.y.zzzz”

TypeScript update breaks SPFx dataVersion - selecting the workspace version

And now the compiler error has been resolved.

TypeScript update breaks SPFx dataVersion - compiler error resolved

That was a nice easy fix for something I didn’t want to have to deal with on a Monday morning but it is what it is.

So we’ve regained control of our environment and been able to implement our workload.

But, was this intentional?

It absolutely was; properties-overridding-accessors-and-vice-versa-is-an-error…

But where does that leave us? Hard to know… On one hand, we can’t just ignore it, but on the other the onus is on the SPFx/pnp teams to resolve this issue.

How else can we handle this? I’ve reverted back to using the VS Code version of TypeScript (4.0.2 at the time of writing), and have simply decorated the dataVersion getter as follows:

// @ts-ignore
protected get dataVersion(): Version {
  return Version.parse('1.0');

While this is also less than ideal, it’s a better workaround for when you open projects written by others.

Hope this helps someone.

Until next time…