Phillippe Santana
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NodeJS Console App with TypeScript, linting and testing

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NodeJS Console App with TypeScript, linting and testing

A quick tutorial on how to start a project for a Console App, in NodeJS, with support for TypeScript, linting and testing.

Phillippe Santana's photo
Phillippe Santana
ยทOct 24, 2022ยท

3 min read

Let's dive right into it, lean and mean.

The base project ๐Ÿš€

1) Create your project folder and enter it

2) Run npm init -y

image.png

3) Install the following packages:

yarn add typescript ts-node ts-node-dev @types/node -D

image.png

4) Add the tsconfig.json file in the root and this as content:

{
  "compilerOptions": {
    "target": "es6",
    "module": "commonjs",
    "outDir": "dist",
    "rootDir": "src",
    "strict": true,
    "sourceMap": true,
    "moduleResolution": "node",
    "esModuleInterop": true
  },
  "include": ["src/**/*.ts"],
  "exclude": ["node_modules"]
}

5) Edit package.json to add some useful scripts

"scripts": {
  "build": "tsc",
  "dev": "ts-node-dev --respawn ./src/index.ts",
  "start": "ts-node ./src/index.ts"
},

image.png

6) Add some starter code

Create src/getGreeting.ts with:

export function getGreeting(name: string): string {
  return `Hello, ${name}!`;
}

Create src/index.ts with:

import { getGreeting } from "./getGreeting";

const greeting = getGreeting("John");
console.log(greeting);

7) Run the project

  • Use yarn build to build the project and see the output at /dist
  • Use yarn dev to start your application in dev mode, which will hot-reload upon changes to the code
  • Use yarn start to start your application without hot-reload

Additional capabilities ๐Ÿ“ฆ

Linting ๐Ÿ”Ž

Install the packages:

yarn add eslint typescript @typescript-eslint/parser @typescript-eslint/eslint-plugin -D

Create .eslintrc.js in the root with:

module.exports = {
  root: true,
  parser: "@typescript-eslint/parser",
  plugins: ["@typescript-eslint"],
  extends: ["eslint:recommended", "plugin:@typescript-eslint/recommended"],
};

Create .eslintignore in the root with:

node_modules
dist
.eslintrc.js

Add/modify the scripts in package.json:

"build": "eslint . --ext .ts && tsc",
"lint": "eslint . --ext .ts"

Run the linter with yarn lint. The "build" command now runs the linter as well.

Testing ๐Ÿงช

Install the packages:

yarn add jest ts-jest @types/jest -D

Create jest.config.ts in the root with:

import type { Config } from "jest";

const config: Config = {
  verbose: true,
  preset: "ts-jest",
  testEnvironment: "node",
};

export default config;

Create src/getGreeting.spec.ts with:

import { describe, expect, it } from "@jest/globals";
import { getGreeting } from "./getGreeting";

describe("getGreeting", () => {
  it("should return Hello, John!", () => {
    expect(getGreeting("John")).toEqual("Hello, John!");
  });
});

Add the script in package.json:

"test": "jest"

Modify the exclude clause in tsconfig.json to read:

"exclude": ["node_modules", "src/**/*.spec.ts"]

Run your tests with yarn test.

For a better experience, make sure you have the Jest extension, which will show a side-bar in VS Code, will autorun tests as they are created or modified, and will allow you to right-click to run or debug a test.

Debugging ๐Ÿชฒ

Create .vscode/launch.json with:

{
  // Use IntelliSense to learn about possible attributes.
  // Hover to view descriptions of existing attributes.
  // For more information, visit: https://go.microsoft.com/fwlink/?linkid=830387
  "version": "0.2.0",
  "configurations": [
    {
      "type": "node",
      "request": "launch",
      "name": "Launch Program",
      "skipFiles": ["<node_internals>/**"],
      "args": ["${workspaceFolder}/src/index.ts"],
      "runtimeArgs": ["--nolazy", "-r", "ts-node/register"],
      "sourceMaps": true,
      "cwd": "${workspaceFolder}"
    }
  ]
}

Press F5 or go to the "Run and Debug" tab and hit play to start debugging.

Other features โœจ

Refer to my older post for instructions on how to add support for environment variables, API access and asycn and await.

Bonus ๐ŸŽ

Download the finished starter project from https://github.com/phillippelevidad/nodejs-typescript-starter.


References ๐Ÿ“–

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