- All the applications share the same library, which, for historical reasons, is in `ReactNativeClient/lib`. This library is copied to the relevant directories when building each app.
- In general, most of the backend (anything to do with the database, synchronisation, data import or export, etc.) is shared across all the apps, so when making a change please consider how it will affect all the apps.
Most of the application is written in JavaScript, however new classes and files should generally be written in [TypeScript](https://www.typescriptlang.org/). Even if you don't write TypeScript code, you will need to build the existing .ts and .tsx files. This is done from the root of the project, by running `npm run build`.
All TypeScript files are generated next to the .ts or .tsx file. So for example, if there's a file "lib/MyClass.ts", there will be a generated "lib/MyClass.js" next to it. If you create a new TypeScript file, make sure you add the generated .js file to .gitignore. It is implemented that way as it requires minimal changes to integrate TypeScript in the existing JavaScript code base.
First you need to setup React Native to build projects with native code. For this, follow the instructions on the [Get Started](https://facebook.github.io/react-native/docs/getting-started.html) tutorial, in the "React Native CLI Quickstart" tab.
If there's an error `while loading shared libraries: libgconf-2.so.4: cannot open shared object file: No such file or directory`, run `sudo apt-get install libgconf-2-4`
If you get the error `libtool: unrecognized option '-static'`, follow the instructions [in this post](https://stackoverflow.com/a/38552393/561309) to use the correct libtool version.
If node-gyp does not works (MSBUILD: error MSB3428: Could not load the Visual C++ component "VCBuild.exe"), you might need to install the `windows-build-tools` using `npm install --global windows-build-tools`.
If `yarn dist` fails, it may need administrative rights.
If you get an `error MSB8020: The build tools for v140 cannot be found.` try to run with a different toolset version, eg `npm install --toolset=v141` (See [here](https://github.com/mapbox/node-sqlite3/issues/1124) for more info).
This is an indication that there's an early initialisation error. Try this:
- In ElectronAppWrapper, set `debugEarlyBugs` to `true`. This will force the window to show up and should open the console next to it, which should display any error.
- In more rare cases, an already open instance of Joplin can create strange low-level bugs that will display no error but will result in this white window. A non-dev instance of Joplin, or a dev instance that wasn't properly closed might cause this. So make sure you close everything and try again. Perhaps even other Electron apps running (Skype, Slack, etc.) could cause this?
- Also try to delete node_modules and rebuild.
- If all else fail, switch your computer off and on again, to make sure you start clean.
> How to work on the app from Windows?
You should not use WSL at all because this is a GUI app that lives outside of WSL, and the WSL layer can cause all kind of very hard to debug issues. It can also lock files in node_modules that cannot be unlocked when the app crashes (you need to restart your computer). Likewise, don't run the TypeScript watch command from WSL.
So everything should be done from a Windows Command prompt running as Administrator. You can use `run.bat` to run the app in dev mode.
