Platform

Packem does not have a literal platform option. Instead, the runtime platform a build targets is controlled by three real options on BuildOptions:

• runtime?: Runtime — the runtime environment (Node, browser, edge, etc.)
• environment?: Environment — "production" or "development"
• browserTargets?: string[] — browserslist queries used when transpiling for browsers

runtime

runtime selects the target runtime. The accepted values of the Runtime type are:

type Runtime =
  | "browser"
  | "bun"
  | "deno"
  | "edge-light"
  | "electron"
  | "node"
  | "react-native"
  | "react-server"
  | "workerd"
  | undefined;

import { defineConfig } from '@visulima/packem/config'

export default defineConfig({
  runtime: 'node',
})

CLI flag

A --runtime flag exists on packem build, but it is narrower than the config option — it accepts only node or browser:

packem build --runtime node
packem build --runtime browser

Any other value is rejected. To target edge-light, workerd, deno, and the other runtimes, set runtime in your config file.

environment

environment selects the build environment. The Environment type is:

type Environment = "production" | "development" | undefined;

The environment also influences other defaults — for example, minification defaults to true in production and false otherwise. On the CLI, --production and --development (which conflict with each other) set the environment:

packem build --production
packem build --development

browserTargets

browserTargets is an array of browserslist queries used to drive transpilation for browser builds. It defaults to the resolved result of browserslist() (i.e. your .browserslistrc or package.json#browserslist).

export default defineConfig({
  runtime: 'browser',
  browserTargets: ['chrome 58', 'firefox 57'],
})

When the global runtime is "node", browserTargets is cleared, but the resolved value is preserved internally (resolvedBrowserTargets) so that individual browser-runtime entries in an otherwise Node package keep their intended targets.

Related Options

• Target - JavaScript language/feature targets
• Transformers - The engine that performs transpilation
• Bundler - Choose the bundler backend