Native .jws Format & Autosave
The native .jws project format and autosave behavior.
The native format is the only way to save a JW Slope model losslessly. A .jws
file holds the entire project — every group and scenario, with all geometry,
materials, loads, water, support, and settings. Computed results are stored
separately in a .jwsr sidecar. JW Slope also keeps a working copy of your
project in browser storage so you do not lose unsaved work between sessions.
Everything is stored locally. Project files are saved to and loaded from your own machine; nothing is uploaded.
The .jws project file
The .jws file is a SQLite database. Inside it are tables for the project
metadata, the scenario groups and scenarios, per-scenario compute settings, the
material and support catalogs, and all geometry (boundaries, regions, loads,
supports, weak layers, tension cracks, and boundary conditions).
| Property | Value |
|---|---|
| Extension | .jws |
| Container | SQLite database |
| Scope | The whole project (all groups and scenarios) |
Saving and loading
Where the browser supports the File System Access API, JW Slope saves and opens files directly through the native file picker (and can write back to the same file). In browsers without that API, it falls back to a standard file download for saving and a file upload for opening.
The .jwsr results sidecar
Computed results are not stored inside the .jws file. They are written to a
separate results sidecar with the .jwsr extension, also a SQLite database.
Each cached result is keyed by scenario plus input hash — the same input hash described in Scenarios. This means a saved result stays valid only for the exact inputs that produced it. If you change a scenario's inputs and recompute, the new result is stored against the new hash, and stale results no longer match.
| Property | Value |
|---|---|
| Extension | .jwsr |
| Container | SQLite database |
| Cache key | Scenario ID + input hash |
Autosave
JW Slope autosaves a working copy of the current project to your browser's
localStorage. This is separate from the .jws file and serves to recover
your session if the tab is closed or reloaded.
- The autosaved state includes the active tab, material and support catalogs, geometry, regions, loads, the scenario hierarchy with snapshots, and view settings.
- Autosave is triggered as you edit the model (debounced by comparing a signature of the state so identical states are not re-saved).
- If browser storage runs low, autosave degrades gracefully: it first trims cached results, then drops scenario result data, keeping the active scenario's geometry as long as possible.
Autosave to browser storage is a convenience, not a backup. It can be cleared
by the browser and is specific to one browser on one machine. Save a .jws
file to preserve your work durably and to move it between machines.