Creating Simple NPM Package

Introduction

In this guide, we will create a simple NPM package that checks if a given input is "null, undefined, or an empty string". This package can be useful for various validation tasks in JavaScript projects. We will cover everything from setting up a new package to publishing it on NPM.

Prerequisites

Before we start, make sure you have the following:

Node.js installed on your system
Basic knowledge of JavaScript and NPM
An NPM account for publishing the package (if you don't have one, you can sign up at npmjs.com/signup)

Step 1: Setting Up the Project Structure

First, let's create a new directory for our project:

mkdir is-empty-input
cd is-empty-input

Next, initialize the package with 'npm init':

npm init

Follow the prompts to enter the package name, version, description, entry point, test command, etc. For this guide, let's keep the defaults except for:

name: 'is-empty-input'
description: "A simple package to check if input is null, undefined, or an empty string"
entry point: 'index.js'

Step 2: Creating the Package Code

In the root directory, create the main file 'index.js':

touch index.js

Open 'index.js' and add the following code:

function isEmptyInput(input) {
  return input === null || input === undefined || input === '';
}

module.exports = isEmptyInput;

This simple function checks whether the provided input is "null, undefined, or an empty string" and returns "true" or "false" accordingly.

Step 3: Adding Tests

It's a good practice to include tests with your package. Create a 'test' folder and add a test file:

mkdir test
touch test/test.js

Add some test cases to 'test/test.js':

const assert = require('assert');
const isEmptyInput = require('../index');

describe('isEmptyInput', () => {
  it('should return true for null', () => {
    assert.strictEqual(isEmptyInput(null), true);
  });

  it('should return true for undefined', () => {
    assert.strictEqual(isEmptyInput(undefined), true);
  });

  it('should return true for empty string', () => {
    assert.strictEqual(isEmptyInput(''), true);
  });

  it('should return false for non-empty string', () => {
    assert.strictEqual(isEmptyInput('hello'), false);
  });

  it('should return false for numbers', () => {
    assert.strictEqual(isEmptyInput(0), false);
  });
});

Your folder structure should look like this:- Completed code structure

To run the tests, install a testing framework like "mocha":

npm install --save-dev mocha

Now run the tests:

npx mocha

Test of node package

All tests should pass if everything is set up correctly.

Step 4: Preparing for Publishing

To publish your package to NPM, you need to log in. Use the following command to log in with your NPM account:

npm login

Follow the prompts to enter your username, password, and email.

Next, ensure your package.json file has a repository field (if you intend to host the source code somewhere like GitHub) and keywords to help people find your package:

{
  "name": "is-empty-input",
  "version": "1.0.0",
  "description": "A simple package to check if input is null, undefined, or an empty string",
  "main": "index.js",
  "scripts": {
    "test": "mocha"
  },
  "keywords": ["validation", "empty", "null", "undefined"],
  "author": "Your Name",
  "license": "MIT",
  "repository": {
    "type": "git",
    "url": "https://github.com/yourusername/is-empty-input.git"
  }
}

Step 5: Publishing to NPM

With everything set, publish your package to NPM:

npm publish

npm package published If successful, you'll see a message confirming that your package has been published. You can now find your package on NPM and use it in other projects.

npm package published on npm repository

Conclusion 🎉

In this guide, we've created a simple NPM package that checks if a given input is "null, undefined, or an empty string". We initialized a new project, wrote code to implement the package's functionality, added tests, and published it on NPM. This package can serve as a basic utility for various validation tasks. Now that you've created your first package, consider adding more features, writing more comprehensive tests, or improving documentation to enhance its usability and maintainability.

Creating Simple NPM Package

Introduction​

Prerequisites​

Step 1: Setting Up the Project Structure​

Step 2: Creating the Package Code​

Step 3: Adding Tests​

Step 4: Preparing for Publishing​

Step 5: Publishing to NPM​

Conclusion 🎉​