klap 👏

a zero config, zero dependency bundler for tiny javascript packages.

✨ Features

🎉 zero config: bundle your library using only a package.json
💥 zero config: typescript support (just rename *.js to *.ts)
🌟 zero config: code transforms using babel macros
🌈 zero config: code generation using babel plugin codegen
🚀 zero dependency: uses gcc-style bundling.
🐙 creates tiny bundles for multiple output formats cjs, esm and umd
🔥 Modern JS syntax with class properties, async/await, and generators
⚡ Built in Minification and Gzip Size Tracking
🌀 Built in development server for quick prototyping.
🎊 Supports react, styled-components and emotion out of the box.

💪 Powered By

rollup - Next-generation ES module bundler
babel - The compiler for next generation JavaScript
typescript - Typed JavaScript at Any Scale.

🍽️ Usage

First, initialize your project using klap init:

npx klap init

Prefer Typescript ? initialize using ts argument:

npx klap init ts

Want to use JSX with Typescript? init using tsx argument:

npx klap init tsx

The init command will create a minimal package.json with source, main, module and browser entries and the build, watch and start scripts.

{
  "name": "...",
  "version": "0.0.0",
  "files": [ "dist" ],
  "source": "src/sum.js",         # source file of your package
  "main": "dist/sum.cjs.js",      # commonjs bundle target
  "module": "dist/sum.esm.js",    # esm bundle target
  "browser": "dist/sum.js",       # umd bundle target
  "scripts": {
    "build": "klap build",        # bundle your package
    "watch": "klap watch",        # bundle your package and watch for changes
    "start": "klap start",        # start a development server
  },
  "devDependencies": {
    "klap": "3.2.0"               # klap as dev dependency
  }
}

Note: Dropping pkg.main will disable cjs output, also applies to esm and umd outputs.

Then use npm run or yarn to invoke npm scripts as you normally would.

See examples for common use cases using klap.

💢 Granular Control

klap uses sensible defaults for most part. However, as needed, use below properties in package.json to fine tune klap. You can also use cli flags to control config options for klap.

option	cli flag(s)	description	default
`source`	-s --source	source file to compile and bundle	`src/index.js`
`cjs`	-c --cjs	the output file for common js format	pkg.main
`esm`	-e --esm	the output file for esm format	pkg.module
`umd`	-u --umd	the output file for umd format	pkg.browser
`types`	-t --types	the output file for type definitions	pkg.types
`browserslist`	-b --browserslist	browserslist compatible compilation target	`last 2 versions modern browsers if usage is greater than 1%`
`klap.name`	-n --name	package name for `umd` bundles	sanitized `pkg.name`
`klap.port`	-p --port	port for development server	`1234`
`klap.example`	--example	location of index js/ts file for start command	`public/index.js` or `pkg.source`
`klap.fallback`	--fallback	location of index html file for start command	`public/index.html`
`klap.target`	--target	target for development server (`umd, es`)	`es`
`klap.sourcemap`	--no-sourcemap	sourcemaps for builds	`true`
`klap.minify`	--no-minify	minification for builds	`true`
`klap.runtime`	--runtime	the runtime for new JSX transform	`react`
`klap.pragma`	--pragma	the JSX Pragma for classic runtime	`react`
`klap.pragmaFrag`	--pragmaFrag	JSX Fragment pragma	`react`
`klap.usets`	--usets	use typescript compiler for the project	`false`
`klap.globals`		global names for umd bundles	`{}`

--usets allows the library code to use typescript features not supported by @babel/preset-typescript. See const-enums example to enable usage of const enums.