Nodejs NPM

Table of Content

Introduction

npm is the world's largest software registry (npm docs). it consists of three major components:

the website to discover packages, set up profiles, and manage other aspects of your npm experience.
The CLI runs from a terminal, and is how most developers interact with npm.
The registry is a large public database of JavaScript software and the meta-information surrounding it.

Common package configuration

package that gets used among projects

easy exporting and importing

To get a better importing experience of the common package (import {requireAuth} from "@maguas/common"; instead of import requireAuth from "@maguas/common/src/requireAuth";) the following is recommended:

index.js with all files being exported

// Re-export stuff from errors and middlewares

export * from './errors/bad-request-error'
export * from './errors/custom-error'
export * from './errors/database-connection-error'
export * from './errors/not-authorized-error'
export * from './errors/not-found-error'
export * from './errors/request-validation-error'

export * from './middlewares/current-user'
export * from './middlewares/error-handler'
export * from './middlewares/require-auth'
export * from './middlewares/validate-request'

add the main file property and the declarations property

{
  "main": "./build/index.js",
  "types": "./build/index.d.ts",
  "files": [
    "build/**/*"
  ]
}

add this useful scripts to package.json

{
  "scripts": {
    "clean": "rimraf ./build",
    "build": "npm run clean && tsc",
    "pub": "git add . && git commit -m \"Updates\" && npm version patch && npm run build && npm publish --access public "
  }
}

set these properties in tsconfig.json

{
  "declaration": true,
  "outDir": "./build",
  "esModuleInterop": true,
  "skipLibCheck": true,
  "forceConsistentCasingInFileNames": true
}

Favorite libraries

LERNA

A tool for managing JavaScript projects with multiple packages. lerna docs

lerna.json

{
  "name": "root",
  "private": true,
  "devDependencies": {
    "lerna": "^4.0.0"
  },
  "scripts": {
    "start": "lerna run start --parallel"
  }
}

package.json

{
  "name": "root",
  "private": true,
  "devDependencies": {
    "lerna": "^4.0.0"
  },
  "scripts": {
    "start": "lerna run start --parallel"
  }
}

PM2

PM2 is daemon process manager that will help you manage and keep your application online. Getting started with PM2 is straightforward, it is offered as a simple and intuitive CLI, installable via NPM. (pm2 docs)

command used for executing a npm script

pm2 start npm --name "{app_name}" -- run {script_name}

command to log any pm2 application running

pm2 logs

command to monitor an application (memory usage)

pm2 monit

Commander

Here is an example of how to use commander

package.json

{
  "name": "@maguas/jsnote",
  "version": "1.0.0",
  "description": "",
  "scripts": {
    "start": "tsc --watch --preserveWatchOutput",
    "test": "echo \"Error: no test specified\" && exit 1",
    "prepublishOnly": "esbuild src/index.ts --platform=node --outfile=dist/index.js --bundle --minify --define:process.env.NODE_ENV=\\\"production\\\""
  },
  "files": [
    "dist"
  ],
  "bin": "dist/index.js",
  "publishConfig": {
    "access": "public"
  },
  "keywords": [],
  "author": "",
  "license": "ISC",
  "dependencies": {
    "@maguastupaguas/local-client": "^1.0.0"
  },
  "devDependencies": {
    "@maguastupaguas/local-api": "^1.0.0",
    "@types/node": "^14.14.31",
    "commander": "^7.1.0",
    "esbuild": "0.8.26",
    "typescript": "^4.2.2"
  }
}

tsconfig.json

{
  "compilerOptions": {
    "target": "es5",  
    "module": "commonjs",
     "outDir": "./dist", 
    "strict": true,     
    "esModuleInterop": true,
    "skipLibCheck": true,                       
    "forceConsistentCasingInFileNames": true
  }
}

#!/usr/bin/env node

import {program} from 'commander'
import {serveCommand} from "./commands/serve";

// comment

program
    .addCommand(serveCommand)

program.parse(process.argv)

./src/commands/serve

import {Command} from "commander";
import path from "path";
import {serve} from "@maguastupaguas/local-api";


const isProduction = process.env.NODE_ENV === 'production'

export const serveCommand = new Command()
    .command('serve [filename]')
    .description('Open a file for edting')
    .option('-p, --port <number>', 'port to run server on', '4005')
    .action(async (filename = 'notebook.js', options: { port: string }) => {
        try {
            const dir = path.join(process.cwd(), path.dirname(filename))
            await serve(parseInt(options.port), path.basename(filename), dir, !isProduction)
            console.log(`Opened ${filename}, Navigate to http://localhost:${options.port} to edit the file.`)
        } catch (err) {
            if (err.code === 'EADDRINUSE') {
                console.error('Port is in use. Try running on a different port.')
            } else {
                console.log('Here the problem', err.message)
            }
            process.exit(1)
        }
    })

@maguastupaguas/local-api serve index.ts

import express from 'express'
import {createProxyMiddleware} from "http-proxy-middleware";
import path from "path";
import {createCellsRouter} from "./routes/cells";


export const serve = (port: number, filename: string, dir: string, useProxy: boolean) => {
    const app = express()

    app.use(createCellsRouter(filename, dir))

    if (useProxy){
        app.use(createProxyMiddleware({
            target: 'http://localhost:3000',
            ws: true,
            logLevel: 'silent'
        }))
    } else {
        // WHY resolve???
        const packagePath = require.resolve('@maguastupaguas/local-client/build/index.html')
        app.use(express.static(path.dirname(packagePath)))
    }

    return new Promise<void>((resolve, reject) => {
        app.listen(port, resolve).on('error', reject)
    })
}

Concurrently

Run multiple commands concurrently. Like npm run watch-js & npm run watch-less but better. (concurrently docs)

{
  "scripts": {
    "start": "node index.js",
    "server": "nodemon index.js",
    "client": "npm run start --prefix client",
    "dev": "concurrently \"npm run server\" \"npm run client\""
  }
}

Ngrok

Ngrok exposes local servers behind NATs and firewalls to the public internet over secure tunnels. (ngrok docs)

Expose a web server on port 80 of your local machine to the internet

ngrok http 80

Nodejs NPM

Table of Content

Introduction

Common package configuration

easy exporting and importing

Favorite libraries

LERNA

PM2

Commander

Concurrently

Ngrok

Nodemon

questions?

What is `"bin": "dist/index.js",`?

what is this script used for `"prepublishOnly": "npm run build"`?

What is the use of `"files": ["dist"],` in package.json?

What is the use of `"engines": { "node": "14.15.0", "npm": "6.14.8"},` in package.json?

Nodejs NPM

Table of Content

Introduction

Common package configuration

easy exporting and importing

Favorite libraries

LERNA

PM2

Commander

Concurrently

Ngrok

Nodemon

questions?

What is "bin": "dist/index.js",?

what is this script used for "prepublishOnly": "npm run build"?

What is the use of "files": ["dist"], in package.json?

What is the use of "engines": { "node": "14.15.0", "npm": "6.14.8"}, in package.json?

What is `"bin": "dist/index.js",`?

what is this script used for `"prepublishOnly": "npm run build"`?

What is the use of `"files": ["dist"],` in package.json?

What is the use of `"engines": { "node": "14.15.0", "npm": "6.14.8"},` in package.json?