Simple Express Boiler Plate with MongoDB and JWT

This is a simple boiler plate for developing APIs using Express JS.

Since Express doesn't restrict you to a specific directory structure you have the freedom to follow any directory structure you desire.

I developed this boiler plate to set myself a directory structure to follow in my projects.

TL;DR Rules

• Don't write business logic inside Controllers
• Don't interact with databases inside Controllers
• Services should be pure functions
• Services is the place to write business logic
• Interact with Databases usings ORMs inside the Service layer.
• Don't handle Router, Request, Response or anything related to http or Express.js inside Services
• util folder contains functions used globally in the project
• All configrations should be inside config.js file and never hardcoded.
• P.S Remove unnecessary console logs in production

Description

The Project structure can be divided into three main components

1. API resource routes
2. Controllers (Route Logic)
3. Services (Business Logic)

In the above Components only 1 and 2 should contains Express.js code. The seperation of Controller and Business logic is to

• Facilitate Unit Testing Functionality without API calls.
• Incase a need arises to call business logic from a CLI tool in the future.
• More clean code.
• Express, Req and Res handling is done in the controller.
• Business Logic is done in the service

How to start

Start the app for development using the coommand npm run devstart

What's included ?

• Directory structure for versioning api
• Separation of Express code and business logic and Database
• Logging using Morgan
• Mongoose connect configuration
• Loading configs based on NODE_ENV
• Utility functions
• JWT JSON Web Token

About Files and Folders

Name	Function
src	Project folder
app.js	Starts server, loads express middlewares and other initial functions needed at the start of server
models	Contains MongoDB Mongoose Schema
services	Contains business logic
api/	Contains api versioning folder and middlewares folders
api/v1/resource	Every API resource should have folder containing routes.js file and Controllers
api/v1/resource/routes.js	Routes path to controllers
api/v1/resource/controller	Route logic for the resources. Calls the required service function

Sevices

• Services should be pure functions
• These function can be used in unit tests
• Business Logic should be inside service layer
• Interaction with Database using ORM is done in Services layer
• Move your business logic away from the express.js router
• Don’t pass the req or res object to the service layer
• Don’t return anything related to the HTTP transport layer like a status code or headers from the service layer
• Always use try catch
• Throw the errors from catch

Controllers

• The controllers are inside api routes
• The controllers contain route logic.
• They do functions such as - Sanitizing the request body data - Extracting query params
• They call the middlewares if there are any.
• They call the respective service functions with the required parameters
• Always use Try...Catch
• Call next(error) inside catch

Env and Config

• All app configurations are stored in config.js
• You can store some configs directly in the file and some as env variables
• env values can be loaded using process.env.VARIABLE_NAME
• You can also store configs directly in the config.js
• Make sure to save confidential values like db connection string and JWT Secret key as environment variables

Development and Production configs

• There are two configs one for development and one for production
• This is done in case we need to have different config values for different environments
• They are loaded based on the process.env.NODE_ENV value. Default is development
• You can also add staging environment and edit the if...else statement at the end of the config.js file

Environment Variables in development

To load env variables in development we have used dotenv npm package. Its loaded at the beginning of the app.

Recommended Configs

Its recommended to have the following environment variables or configs

• dbConnectionString
• port
• corsOptions
• morganLogType

MongoDB Configuration

• Create a .env file
• Create a env resource named DB_CONNECTION_STRING = connectionstring
• This boiler plate uses Mongoose to connect with MongoDB
• The db connection function is inside src/util/dbConnect.js

Demo API calls

GET

Url : localhost:8000/v1/food

POST

Url : localhost:8000/v1/food
Body : {
    "foodToAdd": [
        "banana",
        "strawberry"
    ]
}