Implementation:Promptfoo Promptfoo Tsdown Build Config

Knowledge Sources	Promptfoo_Promptfoo
Domains	Build_System, Configuration
Last Updated	2026-02-14 07:45 GMT

Overview

Build configuration for tsdown (TypeScript bundler) that defines four output targets: server ESM, CLI binary ESM, library ESM, and library CJS.

Description

The Tsdown_Build_Config (tsdown.config.ts) defines four build configurations using tsdown's defineConfig: (1) Server ESM build for src/server/index.ts, (2) CLI binary ESM build for entrypoint.ts and main.ts with a #!/usr/bin/env node banner, (3) Library ESM build for src/index.ts with tree shaking, and (4) Library CJS build for backward compatibility. All builds inject compile-time constants (VERSION, POSTHOG_KEY, MIN_NODE_VERSION, BUILD_FORMAT) and externalize bare module imports for Node.js resolution.

Usage

This file is read by tsdown during npm run build. It defines how the TypeScript source is compiled and bundled for distribution.

Code Reference

Source Location

• Repository: Promptfoo_Promptfoo
• File: tsdown.config.ts
• Lines: 1-129

Signature

import { defineConfig } from 'tsdown';

export default defineConfig([
  { /* Server ESM */ },
  { /* CLI binary ESM */ },
  { /* Library ESM */ },
  { /* Library CJS */ },
]);

Import

# Consumed by tsdown CLI
npx tsdown  # reads tsdown.config.ts automatically

I/O Contract

Inputs

Name	Type	Required	Description
package.json	File	Yes	Read for version constants
PROMPTFOO_POSTHOG_KEY	env var	No	PostHog key for production builds

Outputs

Name	Type	Description
dist/src/server/index.js	File	Server ESM bundle
dist/src/entrypoint.js	File	CLI binary with shebang
dist/src/main.js	File	CLI main module
dist/src/index.js	File	Library ESM bundle
dist/src/index.cjs	File	Library CJS bundle

Usage Examples

# Build all targets
npm run build

# Watch mode for development
npm run build:watch

# Clean build
npm run build:clean && npm run build

Related Pages

• Environment:Promptfoo_Promptfoo_Node_Runtime