is probably the most important file in the Firefox front-end,
since it contains most of the JS code used by the main browser
window. It’s also one of the biggest, at ~7500 lines.
It’s a bit of a dumping ground, since it’s the
most obvious place for main-window-scoped JS code to live, and
there’s a lot of unrelated code spread throughout the
The idea of cleaning it up has been brought up several times
in the past. We have made some changes that help –
landed recently and helps reduce some of the XPCOM boilerplate
overhead (though there’s a bunch of it left!), and
Dão, Mano, and others
have done some
with piecemeal cleanup of cruft in various areas. It remains a
gigantic file, though, and I’d like to try taking some
bigger steps towards improving maintainability and
approachability. I suspect those words could mean different
things to different people, though, so I’m looking for
some feedback or ideas about what exactly should be done. Here
what I was thinking:
Split it up into multiple files
Splitting the code into several separate files and combining
them at build time could help make things more organized. The
idea would be to group pieces of code that are related to each
other or that share the same purpose. We already do this for
some of the places code, for example. I’m not sure how much of a benefit we
could get out of extending this technique, though, since there
are a lot of small unrelated pieces, and hundreds of small
scattered files could certainly end up sucking more than one
humongous file. Getting the right balance might be tricky.
Move “static” methods to a common JS module
Some code in the file is general enough that it doesn’t
need to be loaded for each browser window, and some pieces of
code can be re-factored to make this possible. This would have
the additional benefit of reducing the amount of JS that needs
to be loaded/parsed for subsequent window opens, since JS
modules are shared globally and only loaded once.
Just delete stuff!
The most obvious way to make browser.js more manageable is to
just outright remove code! We’re always on the lookout
for dead code, but I’m sure there’s a bunch of
dead(ish) code still present that’s ripe for removal.
There’s also not-so-dead code that we need to take a
very hard look at. Going down that path
can certainly be controversial, but we have
for several such ideas already, and I think it’s a path
we need to explore further.
Have any other ideas? Let me know in the comments, or even
better, file a bug and mark it blocking