CI Environment Support

tsdown automatically detects CI environments and allows you to enable or disable specific features depending on whether the build runs locally or in CI.

CI Detection

tsdown detects CI from the CI environment variable. CI mode is enabled when process.env.CI is set to a value other than 0 or false (case-insensitive).

CI-Aware Options

Several options support CI-aware behavior through the 'ci-only' and 'local-only' values:

Value	Behavior
true	Always enabled
false	Always disabled
'ci-only'	Enabled only in CI, disabled locally
'local-only'	Enabled only locally, disabled in CI

Supported Options

The following options accept CI-aware values:

• dts — TypeScript declaration file generation
• publint — Package lint validation
• attw — "Are the types wrong" validation
• report — Bundle size reporting
• exports — Auto-generate package.json exports
• unused — Unused dependency check
• devtools — DevTools integration
• exe — Standalone executable generation
• failOnWarn — Fail on warnings (defaults to false)

Basic Usage

Pass a CI option string directly:

tsdown.config.ts

import { defineConfig } from 'tsdown'

export default defineConfig({
  // Only generate declaration files locally (skip in CI for faster builds)
  dts: 'local-only',
  // Only run publint in CI
  publint: 'ci-only',
  // Fail on warnings in CI only
  failOnWarn: 'ci-only',
})

Object Form

When an option takes a configuration object, you can set the enabled property to a CI-aware value:

tsdown.config.ts

import { defineConfig } from 'tsdown'

export default defineConfig({
  publint: {
    enabled: 'ci-only',
    level: 'error',
  },
  attw: {
    enabled: 'ci-only',
    profile: 'node16',
  },
})

Config Function

The config function receives a ci boolean in its context, allowing dynamic configuration:

tsdown.config.ts

import { defineConfig } from 'tsdown'

export default defineConfig((_, { ci }) => ({
  minify: ci,
  sourcemap: !ci,
}))

Example: CI Pipeline

A typical CI-optimized configuration:

tsdown.config.ts

import { defineConfig } from 'tsdown'

export default defineConfig({
  entry: 'src/index.ts',
  format: ['esm', 'cjs'],
  dts: true,
  // Fail on warnings in CI (opt-in)
  failOnWarn: 'ci-only',
  // Run package validators in CI
  publint: 'ci-only',
  attw: 'ci-only',
})