Reliability and speed

Wander works with files, so reliability and stability matter most to it. Here's what they're built on.

Files are protected from accidents. Every file operation comes with a mandatory set: undo with Ctrl+Z, an entry in the session log, system folder protection, and, for a destructive one, a confirmation with “Cancel” as the default. Deleted files go to the Recycle Bin, and so do files replaced while copying; name conflicts are resolved before the first file is touched. Learn more on the “Working with files” page.

Testing.

• Logic: tests. The decisions that files depend on (what to do on a name conflict, how to undo an operation, what counts as a companion, how to name the result) live in a core with no interface. It's about a third of Wander's code, and it's checked by over two and a half thousand automated tests that cover 91% of its lines.
• Interface: scenarios. Before a release, automated scenarios walk through the real Wander window on a set of test folders: thousands of files, RAW, documents and archives in various formats, names in various languages, paths longer than 260 characters, hidden and locked files. They copy and undo, search, page through the Preview pane, check selection and focus, and verify the result. A long run walks through folders for half an hour, making sure memory doesn't grow.
• Review: by hand. What automation can't see (drag and drop with other programs, other programs' menu items, the look) is checked against checklists by a meatbag before every release.
• Measurements. Each release's size, startup time and memory use are measured and compared with the previous release: a regression stops the release just like a failed test.

Speed.

• A folder appears right away, and the heavy parts load in the background: thumbnails, icons, folder sizes, program signatures.
• Only what's visible on screen is drawn, so a folder of thousands of files scrolls as easily as one of ten.
• RAW shows instantly: both the thumbnail and the Preview pane use the preview embedded in the file, without developing the RAW.
• Neighboring photos are prepared in advance while you look at the current one.
• Thumbnails, once made, are kept in a disk cache, and a folder you've seen before opens faster.
• Long operations run in the background, and the window stays responsive meanwhile. Everything that could slow things down is cached or runs asynchronously.

Openness.

• The source code is open for reading on GitHub.
• The release Wander.exe is built on GitHub's servers straight from this code, every build's log is public, and the SHA256 checksum next to the file lets you verify that you downloaded exactly that file.
• Wander doesn't go online: no analytics, no ads, no background updates. You send a bug report yourself, if you want to.
• Nothing is written into the system: Wander keeps everything of its own in one folder; see “Data and cache”.
• The author originally wrote the app “for myself”, so it works the way that suits the user, not the publisher.