@packlet/build is a focused, minimal build layer for TypeScript and JavaScript packages. It wraps Bun’s high-performance bundler with a clean, consistent interface tailored for libraries and CLIs—no heavy configuration, no multi-tool orchestration.

If you want a predictable, modern build pipeline with ESM-first output, optional CJS, and automatic type generation, @packlet/build gives you exactly that with a single command or function call.

Use it standalone or as the build engine behind the higher-level packlet CLI.

Features

- ESM by default (dist/index.mjs), with optional CJS output (dist/index.cjs)
- TypeScript declarations generated automatically into dist/
- Fast Bun-based bundling with a single consistent interface
- Simple control over sourcemaps, minification, externalization, and CLI executables
- Programmatic API for embedding in your own tooling

Installation

``sh


with bun

bun add -D @packlet/build

with npm

npm install -D @packlet/build
`

> Note: @packlet/build uses bun build internally. Bun must be installed on the machine running the build (recommended: Bun ≥ 1.2.0).
> For environments without Bun, you may still use the programmatic API with custom bundlers.

Usage via npm scripts

Add build scripts to your package.json:

`jsonc
{
"scripts": {
"build": "packlet-build build --sourcemap none --external-auto",
"build:cli": "packlet-build build --cjs --exec-js --sourcemap none --external-auto"
}
}
`

Run them normally:

`sh
npm run build


or


bun run build
`

Or run the CLI directly using npx / bunx:

`sh
npx @packlet/build build --sourcemap none --external-auto
`

Programmatic API

You can also invoke the builder directly from JavaScript or TypeScript for full control:

`ts
import { build } from "@packlet/build"

await build({
entry: "src/index.ts",
outdir: "dist",
formats: ["esm"],
sourcemap: "none",
types: true,
target: "node",
execJs: false,
minify: true
})
`

This API is ideal for custom workflows, monorepos, or script-driven build pipelines.

CLI flags

packlet-build supports the following build flags:

- --entry : entry file (default: src/index.ts)
- --outdir

: output directory (default: dist)
- --formats : comma-separated formats (default: esm)
- --cjs: shorthand to also emit CommonJS (index.cjs)
- --sourcemap : external or none (default: none)
- --no-types: skip type declaration generation
- --target : build target (default: node)
- --exec-js: mark generated output as executable (helpful for CLIs)
- --no-minify: disable minification (enabled by default)
- --external : specify external packages
- --external-auto: automatically externalize dependencies and peerDependencies

$3

- Type declarations come from tsc --emitDeclarationOnly, always using your local tsconfig.json.
- For debugging, prefer --sourcemap external to keep maps separate from published artifacts.
- Disable minification (--no-minify`) when inspecting bundles locally.

License

MIT © KazViz