Last year we launched Compare view, a feature that allows you to compare any two Git branches, commits or tags and see the difference between them. Compare view is an essential tool for reviewing code before it’s merged back into master. You can see who worked on a branch, every single line of code that changed and other useful information.
Up until yesterday it didn’t become obvious to me that if we pair our Preview tool with Compare view we can end up with something even more awesome: the ability to quickly compare design changes between branches. Sure, we’ve had Preview buttons for each supported file type (HTML & images) in Compare view since the beginning, but it didn’t do the right thing. It used to preview just one version of a file instead of comparing the same references that you had selected in Compare view itself. So I sat down yesterday and made some major improvements to the way Preview buttons work in Compare view.
Now when you click the Preview button on a file in Compare view, a page will open up that has both the old and new designs shown side-by-side in a split view. This makes it super easy to see the difference in design between two branches. Not only you can verify that the code from a branch is solid, but also make sure that it looks great: