Clean out the Junk Mail folder on Mac OS X (aka macOS) Mail using JavaScript.

I get a lot of junk mail. Probably 10x real mail. Apple's Mail program is good at finding it and moving it to the junk mail folder, but after a while, it can really accumulate. I'd like to not just mass-delete everything in there; I still have the occasional piece of real email that lands in junk. But when I had over 10k junk mail items in there, I knew I was never going to be able to review them all.

I tried creating filters in Mail that would clean it out, but I could never get them to work. Finally, I decided would use the scripting system built into OS X (or macOS, by the time you read this). And, since I know JavaScript, I figured I'd use JS to do the work.

Sounds simple! Hours and hours and hours later, it's done. Not quite so simple, but I figured I'd share it to save the next person the same grief...

The script you see here will run through every message in your junk mail folder and delete any that match a pattern for the sender or for the subject. I discovered that spam almost always has a sender that looks like a subject, and so even though they use a massive number of email accounts, they tend to be from "Airline Tickets", or "Alcohol Rehab Centers", etc.

It will also delete any junk mail that's over a certain age (e.g., 60 days).

The actual list reflects what I found in my junk folder, and I expect that it will change over time. So don't take my list as anything other than useful examples.

There are three sections at the top of the script that you should configure:

1. The maximum age of junk mail
2. The list of rules to match against senders
3. The list of rules to match against subjects

The age configuration is fairly straightforward. Find the line that reads something like:

var	age_limit = 60 * day_in_milliseconds;

and change the number to whatever limit, in days, you wish. I picked 60 because I figure after two months if I haven't noticed a piece of junk mail isn't junk, it probably wasn't important either.

The next two sections define regular expressions to match against the sender and subject of each piece of junk mail.

Essentially, any line of code that looks like:

senders.push(/beverly hills/i);

means that it's adding a pattern for (in this case) the sender (aka from) to spot as being junk mail. You can use any regular expression you wish, but if you're not comfortable with regular expressions just replace the text between the two / and you'll be fine. If you have punctuation in your pattern (for example, . or $), you'll want to put a backslash \ in front of it because those have special meaning.

You can add, subtract, or modify any of the senders.push() or subjects.push() lines as you see fit.

The top section of the application contains the "configuration": it defines the age limit and builds up the sender and subject rules.

Next, the code connects to the Mail app and gets a list of junk mail messages, and then builds up its list of patterns.

It then loops through all of the messages, one at a time, and compares the message's sender against all the sender rules (stopping if there's a match), then the messages subject against all the subject rules (again, it stops when there's a match), and, finally, compares the message's age against the limit.

If any of the rules or limit hits, the message is marked as being deleted.

A status message is returned indicating the results of the process.

If the Mail program refreshes while your script is running it seems to cause an error. No worries, just run it again.

The documentation for writing JavaScript scripts on macOS is not very complete, and so this code is a result of experimentation not solid design. So if something seems quirky or odd in it, it probably is not intentional.

If you run the program multiple times in quick succession, it seems to find and re-delete previously deleted messages, so the count does not go down. Quit and restart Mail to solve this. Or fix it and send me pull request...