Double-Booked: A reactive web app for double-entry accounting
This is an app for double-entry accounting, in the tradition of GnuCash and Ledger. It is designed in a reactive style, with the goal of having a highly responsive UI where updates propagate immediately and you don't "generate a report", you just view it (with instant results).
It is designed to run in a web browser, client side, using indexedDB as its data store (though with the ability to sync to a centralized server).
I have lots of big ideas for how I want to improve on existing accounting apps. But as a backend guy, I am primarily focused right now on creating a data storage layer that has all the features I want. I want to make sure the data model is rich and powerful (hierarchical accounts, multiple currencies, stocks/bonds with lot/basis info, balance assertions), but also highly efficient. Propagating updates efficiently in an accounting ledger is a hard problem that I discuss at length in DBDesign.md.
Basically I'm trying to create the "git" of double-entry accounting. Git's primary contribution is its efficient data model and storage format. It is the basis on which the entire ecosystem is built.
Build / Run / Test
You need Node.js.
Install these tools if you don't have them globally installed already:
$ npm install -g bower
$ npm install -g gulp
Then install our dependencies into the local tree (it reads
the list of packages to install from bower.json and
package.json):
$ bower install
$ npm install
Now build/transpile all the source and create a
fully-populated output directory in build/:
$ gulp
Now you can run the app by visiting build/index.html
(not much to see right now though).
To run the tests visit tests/test.html. I have verified
they work in both Chrome 43 and Firefox 39.
Overall Design / Technologies
The data storage layer is in model and written in ES6. It only depends on:
- a red-black tree, since JavaScript doesn't natively provide a sorted map.
- indexedDB, for storing the data locally
Because of the second dependency, it requires a web browser (there doesn't appear to be a robust implementation of indexedDB for Node.js).
The storage layer is by far the most interesting and mature
part of the project so far. Between the design
doc and the source comments, it should be
pretty usable. It is also tested reasonably well by the
tests in tests.
The (very minimal) UI is built on React and ReactRouter. It uses some minimal UI framework in the form of Pure and FontAwesome.
Since the app is designed to be capable of working completely offline, it is intended to be usable as a Chrome App or with ServiceWorker. I'm keeping my options open on this point.
My hope is to implement syncing with a server using a flat file on Google Drive or DropBox. So you'd have a local database in indexedDB, but you could push your commit log to Google Drive and pull commits from it. A key idea here is that it should sync to storage owned and controlled by the user, not servers that I operate.