Talk:JavaScript Preferences Class
From MozillaZine Knowledge Base
Regarding default values for prefs
There's a concept of Default preferences in Mozilla prefs system. I really like it and prefer using it over using methods like get*PrefDef(aPrefName, aDefaultValue)
(that is, wrapping calls to prefs XPCOM in try { } catch blocks or checking value type), because:
- All default values are in one place, where they can easily be reviewed and changed.
- In particular, if you read a pref in two different parts of code, you don't have to duplicate default values, as you would have to, if you were using get*PrefDef.
- The prefs read from 'defaults' files are displayed in about:config, helping power users to find "hidden" prefs.
- Support for locked prefs - for free.
When using 'defaults', wrong type of a preference or anything else that makes get*Pref method of nsIPrefBranch fail, is an exception and should be handled as such instead of just silently putting a hard-coded default value there.
Hi Asqueella, How does an extension install default preferences? I was trying to solve the problem which arises when default preferences do not exist.