Run npm install and npm start.
To use nodemon to restart when changes are made run npm run-script dev.
Some simple tests can be ran with npm test.
I've limited the maximum query size to 12 letters (arbitrarily), but even that can take a little while or timeout on a platform like Heroku.
I've added a 1 second timeout to the Ajax request so it doesn't wait forever.
A smarter algorithm could make this less of an issue, but at some stage you're still searching for a needle in a haystack.
Additionally I could store anagrams of words as they're generated for later lookup, or pre-process words in a worker.
MIT License
http://dreamsteep.com/projects/the-english-open-word-list.html
UK Advanced Cryptics Dictionary Licensing Information:
Copyright © J Ross Beresford 1993-1999. All Rights Reserved. The following restriction is placed on the use of this publication: if the UK Advanced Cryptics Dictionary is used in a software package or redistributed in any form, the copyright notice must be prominently displayed and the text of this document must be included verbatim.
There are no other restrictions: I would like to see the list distributed as widely as possible.