es6pkg

This is a sample/starter project for building a library package, including bundles in three formats: UMD, CJS and ES.

The build pipeline uses Babel and Rollup to transpile and bundle your JavaScript code for the required deployment scenarios: UMD for browser script tags; CommonJS (CJS) for NodeJS applications using require statements; and ES for applications using ES6 import statements.

Your package code can be developed using ES6 (ES2015) features of JavaScript, including export and import statements.

Installation

git clone [email protected]:jlafer/es6pkg.git <pkgname>
cd <pkgname>
npm install

Usage

The sample source files can be removed from the /src sub-folder, where you can place your project's source code. Code development can proceed using ES2015 features, as Babel is used in the build process to transpile all source files to ES5-compliant format.

If the package is imported using CommonJS require statements, all properties of the package will be imported. If imported using ES6 module import statements, then tree-shaking will be performed and only the required properties of your package will be bundled into the consuming application.

Use npm run build to build and bundle the package files in the /dist sub-folder.

Testing

As this package is designed for building library packages, the suggested (i.e., TDD) development pattern would involve putting functions and their test cases in the package and testing locally. Jest is already included and can be invoked using npm test. The babel-jest package is installed along with a babel.config.js file, so Jest automatically transpiles ES6-style test files prior to execution. See src/index.test.js for a sample test case file.

Local Usage

During active development you can also use the npm run dev command to run Rollup in "watch" mode - the executable packages are updated as changes are saved to the source files. So, for instance, if you put calling code in index.js you could run it in NodeJS using the command node dist/bundle.cjs.js.