CRDT Spreadsheet

This demo app shows a collaborative application developed using a draft implementation of the Concordant API. The application uses the C-Service API which currently supports two eventual consistency backends: revision-based and CRDT-based. This demo shows that with a revision based approach, the user loses updates, either if updates are executed concurrently online, or if multiple users edit the document offline. To have an adequate semantics, the user needs to provide custom, non-trivial, code to merge the updates executed by each user. With the CRDT-based backend, update convergence is available out-of-the-box.

The current demo is implemented on top of PouchDB which offers replication and offline support. Later we will implement our backed without any third-party dependencies.

Setup guide

0.Requirements

For the next steps, you will need the following software:

• Make sure you have the latest version of Node.js: see official installation guide;

• The project uses Git to download some required dependencies: follow the official install guide

  1.Install Project dependencies

Go to project root directory and:

npm install

2.Run the application

npm start

3.Build for server production-ready deployment

npm install

# and enable CORS in CouchDB using the fetched script
# If your CouchDB instance is password protected, use -u <user> -p <password> options:
node node_modules/add-cors-to-couchdb/bin.js

# Then build the app using:
REACT_APP_SERVERURL="http://${MY_SERVER_ADDR}:5984/${MY_DBNAME}" \
REACT_APP_OFFLINE_FIRST=any \
npm run build
# Note: REACT_APP_OFFLINE_FIRST=any Enables Service Workers to run application offline

The build directory will now contain a static JS you can deploy in your server.

Replication support

If you want to run with cross-replica synchronization, just run a CouchDB Server, see CouchDB's installation guide

Requirements (versions)

Node: v10.15+ NPM: v6.13+

(Project might work with older Node and NPM versions)