To use the examples in this repo, clone the repo and cd into the example directory you want to try (e.g., break-away). You can also create new app folders and write your own! Refer to the config files (e.g., package.json, tsconfig.json) in break-away or other example app directories for what you'll need.
Be sure to check out the example app's README for any instructions related to that app.
JustIn requires a MongoDB server with replica sets in order to work. These instructions cover how to set up a local instance of MongoDB for testing and playing with the examples.
Download MongoDB community edition
On Mac, create a /data/mdata directory in your home directory ($ mkdir ~/data/mdata).
On Windows, create a \data\db directory at the top level of your C: drive, or (mkdir c:\data\db).
In your command line/terminal:
mongod --port 27017 --dbpath ~/data/mdata --replSet rs0 --bind_ip localhost
This will need to stay running while any example apps are running. For information about other ways to install and run MongoDB, including running it as an always-available service, see the MongoDB documentation for your OS.
If you want to see the data that JustIn creates and modifies in Mongo, you can use MongoDB compass for exploring the DB, or you can use mongosh from the command line.