# History++ - A Better Way to Do Versioning Have you ever had to start over on a piece of code because you overwrote something by accident? Made an edit, replaced it, and then wished you could go back? **Featured image unavailable: Cover artwork for the article “History++ - A Better Way to Do Versioning”.** [Open original](https://replit.com/api/storage/public-objects/article-media/history2-release/sanity-06f44b489e9fea1004ebd8249a0a633f52fd925f.b165f0cbc61dc276.webp) - Published: 2022-09-15T00:00:00.000Z - Authors: Giuseppe Burtini - Canonical: https://replit-engineering-blog.pages.dev/history2-release/ --- Have you ever had to start over on a piece of code because you overwrote something by accident? Made an edit, replaced it, and then wished you could go back? Programmers have tools like `git` and the undo/redo stack to help them deal with challenges like this. Replit, of course, supports these things. But, we think there's a better way. Over the last week, we rolled out the new history UI to general availability. Here's what it looks like: **BunnyVideo embed unavailable: Browsing file history in Replit History++** [Open original](https://player.mediadelivery.net/play/489085/3ea2a323-6fe6-4786-9d93-44e0d2aa386a) ## The Basics First, a bit of background. Whenever you make changes to your code, we add the *[operational transformations](https://en.wikipedia.org/wiki/Operational_transformation)* (OTs) to a log of activity for that file. OTs are part of our multiplayer infrastructure, they effectively store the "intended change" every time you edit a file. We use this for reconciling potential conflicts when many users edit a file simultaneously. It turns out, this makes for a pretty cool approach to versioning and history. You don't have to do anything to benefit from it (it is happening anyway) and it produces a high-fidelity take on the historical states of your file, with no real mental overhead. **Image unavailable: A pointer to the "Repl history" link in the workspace** [Open original](https://replit.com/api/storage/public-objects/article-media/history2-release/sanity-a97dd8d36fde816034d1644a8c8e20ed64b6af00.0caed24871acac19.webp) _A pointer to the "Repl history" link in the workspace_ ## The Utility With version control system based history, like `git`, you have to make an active decision to create a commit, so your intermediary states get lost. Worse, for many users, the concepts and interface are difficult. We love `git`, but it is just a piece of the puzzle. Here, you can browse a file's history, exploring it with the same interface that you normally use, seeing every change that has been made to it, and non-destructively restore to any specific version. We aimed for this to be lightweight, low-risk, and easy to use: a complement to the tools you are already using. **Image unavailable: A screenshot of the new history tool, showing a unit test suite written in JavaScript** [Open original](https://replit.com/api/storage/public-objects/article-media/history2-release/sanity-8ede0fae98c5855896e07e71e47203c431c09817.4de3cae7fe1e5e31.webp) _A screenshot of the new history tool, showing a unit test suite written in JavaScript_ Once you've found a version you think is relevant or interesting, you can toggle on compare mode to see a side-by-side diff. You can also select and copy some subset of the version or click restore to bring your file back to where it used to be. **Image unavailable: A screenshot of a side-by-side diff-view** [Open original](https://replit.com/api/storage/public-objects/article-media/history2-release/sanity-06f44b489e9fea1004ebd8249a0a633f52fd925f.b165f0cbc61dc276.webp) _A screenshot of a side-by-side diff-view_ ## The Fun One really cool way we've been seeing people use this is to use the playback feature -- which lets you watch your file's history like it is a movie -- to make videos of their programming sessions. We're going to do more to support sharing and social integration of these sessions going forward, but for now, it is already a really cool way to retroactively decide to share how you were thinking. Some other neat upgrades: - **Dark mode**: Old history didn't support dark mode. Sorry. New history does though\! - **Mobile support**: Maybe you noticed that old history was real awkward on small screens? Mobile now gets first class history support\! - **General polish**: You can browse the file tree like you would in the rest of your Repl, interact with a particular version like it is your regular code: copy-and-paste, compare, restore, and more.