Preload safe debug shim (#29)

In https://github.com/ferdium/ferdium-app/pull/23 we removed usages of
the debug package due to an electron bug.

This patch aims to restore some debug functionality by introducing a
shim. The shim detect whether if it is being introduced in a preload
script where the electron but would be triggered, and falls back to a
simple replacement for debug. However, in the main and renderer
processes, where a preload script is not being used, we still get full
debug functionality.

In this way, a module can be used both in a preload script and outside
of it, while still preserving debug functionality whenever possible.

Signed-off-by: Kristóf Marussy <kristof@marussy.com>

1 files changed, 2 insertions, 0 deletions

diff --git a/CONTRIBUTING.md b/CONTRIBUTING.md
index 78b9a36be..8f1b19685 100644
--- a/CONTRIBUTING.md
+++ b/CONTRIBUTING.md
@@ -202,6 +202,8 @@ DEBUG_COLORS=1 DEBUG=Ferdium:* npm run start:all-dev
 ```
 
 Note: please prefer [`debug()`](https://github.com/visionmedia/debug) over `console.log()`.
+However, due to an [Electron bug](https://github.com/electron/electron/issues/31689), using `require('debug')` directly is dangerous and can lead to data loss in services.
+Please use the `src/preload-safe-debug` module instead until the bug gets fixed.
 
 ### Styleguide