Creating Node.js Shared Packages using TypeScript

In this article you will learn everything needed to get started with writing your own private or open source package for Node.js in TypeScript.

Initial Skeleton

Let's start by creating a new directory and enter the directory. Please run following command inside the root of your working directory.

Please ensure new directory is empty before running the commands

npm init -y
npm install --save-dev typescript
npx tsc --init

You should now see three additional files at the root of your working directory:

• package.json
• package-lock.json
• tsconfig.json and a folder node_modules containing our development dependency.

npx command allows you to run executable CLI in your dependencies; in this case we utilise it to run tsc with --init flag to create an initial tsconfig.json

TypeScript Configuration

Initial tsconfig.json has many optional fields which are mostly out of scope of this article. However, here we only mention bare minimum required options.

{
  "compilerOptions": {
    "target": "es5",
    "module": "commonjs",
    "rootDir": "./src",
    "moduleResolution": "node",
    "declaration": true,
    "declarationMap": true,
    "outDir": "./dist",
    "inlineSourceMap": true,
    "declarationDir": "./dist/types",
    "esModuleInterop": true,
    "forceConsistentCasingInFileNames": true,
    "strict": true,
    "skipLibCheck": true
  },
  "include": [
    "src/**/*.ts"
  ]
}

Package Configuration

{
  "main": "dist/index.js",
  "types": "./dist/types/index.d.ts",
  "scripts": {
    "build": "rm -rf dist && tsc"
  },
  "private": false
}

Publish the Package

We can publish our package using npm publish command. You could find more information on this command here. In order to ensure published package is always transpiled from TypeScript before running npm publish, we can add additional command to package.json to automate this process. We can add prepublish inside scripts array to remove existing dist folder and transpile and create a new distribution folder.

{
  "scripts": {
    "prepublish": "rm -rf dist && tsc"
  }
}

Credits

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