A Full stack MERN app to track expenses. That is, this is a MERN Expense-Tracker application.

App Structure

The app is divided into two main parts: a sub-directory named client representing reactJs frontend code. Everything else except that folder pertains to a node/express based backend project. Basically, there is a server application and a client application.

The data for the app is stored on the cloud using MongoDB Atlas here: https://www.mongodb.com/cloud/atlas. Signing up and utilizing basic tier is free. The credentials for the DB and any collections has to be used during connection in the backend/express app (refer to the ./config/db.js file for the connection syntax).

How to run the app

There are 4 scripts to run the two applications: start, server, client and dev. These scripts are discussed below:

1. start script: is a node command to run the main nodejs file called server.js. This will start the node/express server in non-monitoring, simple mode.
2. server script: runs the main nodejs file called server.js using the nodemon package in a auto-reloading, monitoring mode. This will allow us to reload the server (only) when something changes in the server based code. This is the preferred mode of running our server.
3. client script: runs the client or React based code that displays a single page with transactions. We utilize the --prefix option to npm start to specify the client sub-folder within the root folder. Change the prefix path based on your client sub-folder location.
4. dev script: utilizes the concurrently package to simultaneously run both the client and the server scripts from above. This is the preferred mode to run during development to allow for debugging as well.

## Very important note (related from environment section below) Before starting the server or any script that starts the server as part of it, please create a env/environment file for the dotenv package to read values from within the server.js file. The way current server.js code is setup the env file has to be named config.env. If you use a different file name, change the name in the dotenv.config code block within server.js.

The environment package and variable gotchas

We utilize the dotenv package to enable us to setup and read environment variables from a .env type file. A sample usage of dotenv is:

    process.env.NODE_ENV === 'development'

which is taken from the server.js file. A .env file allows us to store environment specific variables like the current environment, DB credentials etc. Note the following code from server.js again which configures a file named config.env to be used as the environment variable to be used by the dotenv package:

    dotenv.config({
        path: './config/config.env'
    })

where this code assumes that the configuration file lies within a folder called /config/. Hence, in order to run the app, please create and fill up a configuration file, in this case named config.env.