Friday, September 15, 2017

Updating SPFx package still showing the older web part

Something I noticed while working with SPFx,
some times I would release a new package to my app catalog by dragging it over an existing older version.

SharePoint would prompt me to overwrite, I would say yes.

Now, every page refresh I would randomly get the older file loaded or the latest one loaded. It was completely unpredictable and didn't seem to depend on anything specific I did.

What happens?

It seems when you overwrite a package, you don't get the dialog to trust the package. Now, that dialog is important, since while you visit it, it plants a cookie in your browser that marks for SharePoint to drop its package cache and reload the manifest.
If that cookie is missing... you would be getting a cached version of the manifest.
Since SharePoint Online is a beast with many WFE servers in load balanced setup, you sometimes get a server that cleared its cache (maybe the one that handled the replace action) and other times a server that still has the older one cached.

This situation is not a big deal in production, since in 20 minutes or so the cache clears itself.

But for dev - here is what you have to do to avoid it:
Simply delete the package before you upload a new one, and don't use the overwrite option.

Simple, efficient but very confusing...

Hope this helps!

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