Express ES6 Starter

A custom NodeJS starter project with preconfigurations and templates to help you ship quality code early and often.

Table of Contents

• Express Server
• Code Quality
  • Unit Specs with Jasmine
  • ES Linter
• Development Workflow
  • Preflight Command
• Docker Setup
• Jenkins Pipeline
• Automated Semantic Versioning

Express Server

This project uses Express, a minimalist web framework for Node.js. It's lightweight and great for APIs.

Development

Using nodemon, the express server is automatically restarted when the src directory changes.

npm run server

The server defaults to port 3000. You can change it by setting the PORT environment variable.

Production

In production, run the server using just node:

npm start

Code Quality 👌

Jasmine is preconfigured and an example spec showing how to test Express apps is included. Just as important as testing but often forgotten is linitng. As author of Clean Code Robert Martin wrote:

Consistent indentation style was one of the most statistically significant indicators of low bug density.

Unit Specs with Jasmine

Unit tests leverage the Jasmine testing framework. They are executed with the standard NPM test command.

npm test

Unit specs:

• must use .spec.js as a suffix
• are preferably saved in the /specs, but they will be picked up anywhere
• are executed randomly

For your convenience context() is also aliased to describe(), which helps nested syntax:

describe ('login()', () => {
  context ('valid credentials', () => {
    it ('returns true', () => {
      ...
    })
  })
  context ('invalid credentials', () => {
    it ('returns false', () => {
      ...
    })
  })
})

ES Linter

This project is also linted for code consistency with the recommended rule set, plus some custom changes, most notably:

Semicolons are not allowed:

// OK
let foo = bar

// will error
let foo = 'bar';

Spaces are required before the function parenthesis:

// OK
function (foo) {
  return true
}

// Fails
function(foo) {
  return true
}

Consistent spacing inside curly braces, for example:

// OK
import { app }

// Fails
import {app}

To see all adjustments, see the .eslintrc file.

Autofix Problems

You can autofix most common linting offenses with this command:

npm run lint:fix

Development Workflow

In development however, you can leverage auto reloading with:

npm run dev

which will simultaneously run and watch:

• server
• unit specs
• linter

Or you can run them separately:

npm run server
npm run lint:watch
npm run test:watch

Preflight Command

Before I push code, I like to check if it will pass all continuous integration stages with a simple command that runs all the stages:

npm run preflight

If you wanted to, you could also configure a githook to ensure all your commits are green.

Docker Setup

For your convenience, there is an included Dockerfile and docker-compose.yml, which help jumpstart your microservice architecture.

These presets save you from common gotchas:

• Dockerfile: package.json is copied first to avoid the heavy npm install step on successive builds.
• docker-compose.yml: note that node_modules is mounted separately. This is required because native bindings can differ between the container and your development computer.
• Included .dockerignore to avoid copying giant node_modules folder on build.

Note these files are configured for development only. If you plan to use them in production, you will make adjustments, e.g. use a different base image.

Jenkins Pipeline

There is a sample Jenkinsfile which a declarative pipeline including the following common stages:

• checkout
• install dependencies
• run linter
• run unit specs

Automated Semantic Versioning

This project uses standard-version for automatic semantic versioning and change logs.

1. Commit messages must follow the Conventional Commits standard.

2. When you are ready to release, just run:

npm run release

which will automatically:

• update your CHANGELOG.md
• tag your git repository

Depending on your commit messages, standard-version will automatically determine if it's a major, minor or patch release.