create-package-with-typescript.md

• mkdir my-typescript-package && cd my-typescript-package
• Create a git repository

    git init  
    echo "# My typescript package" >> README.md 
    git add . && git commit -m "Initial commit" 
    git remote add origin < Git Repository Url >
    git push -u origin master

• Init your Package (to generate package.json)

    npm init -y

• add .gitignore file to the root.

    echo "node_modules" >> .gitignore

• Add Typescript as a DevDependency

    npm install --save-dev typescript

• to compile Typescript we also need a tsconfig.json

    {
        "compilerOptions": {
        "target": "es2015",
        "module": "commonjs",
        "declaration": true,
        "outDir": "./lib",
        "strict": true
        },
        "include": ["src"],
        "exclude": ["node_modules", "**/__tests__/*"]
    }

Start code

• create index.ts file

    export const PackagePrint = (name: string) => `Printing ${name}`; 

• update package.json

    "build" : "tsc"

• Ignore compiled code in git by adding /lib ot .gitignore file
• Formatting and Linting

    npm install --save-dev prettier tslint tslint-config-prettier

• In the root, add a tslint.json

    {
        "extends": ["tslint:recommended", "tslint-config-prettier"]
    }

• And a .prettierrc

    {
        "printWidth": 120,
        "trailingComma": "all",
        "singleQuote": true
    }

• update package.json scripts section

    "format": "prettier --write \"src/**/*.ts\" \"src/**/*.js\"",
    "lint": "tslint -p tsconfig.json"

• whitelist the files /folders you want to publish by adding files property in package.json

    "files": ["lib/**/*"]

• Setup testing with jest

    npm install --save-dev jest ts-jest @types/jest

• Create a new file in the root and name it jestconfig.json

    {
        "transform": {
            "^.+\\.(t|j)sx?$": "ts-jest"
        },
        "testRegex": "(/__tests__/.*|(\\.|/)(test|spec))\\.(jsx?|tsx?)$",
        "moduleFileExtensions": ["ts", "tsx", "js", "jsx", "json", "node"]
    }

• Remove the old test script in package.json and change it to:

    "test": "jest --config jestconfig.json"

Write a basic test

In the src folder, add a new folder called tests and inside, add a new file with a name you like, but it has to end with test.ts, for example Greeter.test.ts

    import { PackagePrint } from '../index';
    test('My package printer', () => {
    expect(PackagePrint('my typescript package')).toBe('Printing my typescript package');
    });

Run tests

    npm test

Use the magic scripts in NPM

• Add scripts in package.json : prepare, prepublishOnly, preversion, version and postversion

    "prepare" : "npm run build",
    "prepublishOnly" : "npm test && npm run lint",
    "preversion" : "npm run lint",
    "version" : "npm run format && git add -A src",
    "postversion" : "git push && git push --tags"

Finishing up package.json

    {
    "name": "my-typescript-package",
    "version": "1.0.0",
    "description": "A bare minimal package",
    "main": "lib/index.js",
    "types": "lib/index.d.ts",
    "scripts": {
        "test": "jest --config jestconfig.json",
        "build": "tsc",
        "format": "prettier --write \"src/**/*.ts\" \"src/**/*.js\"",
        "lint": "tslint -p tsconfig.json",
        "prepare": "npm run build",
        "prepublishOnly": "npm test && npm run lint",
        "preversion": "npm run lint",
        "version": "npm run format && git add -A src",
        "postversion": "git push && git push --tags"
    },
    "keywords": ["Hello", "PackagePrinter"],
    "author": "adhamankar",
    ....

publish package

    npm login
    npm publish