jiti

This is the active development branch. Check out jiti/v1 for legacy v1 docs and code.

🌟 Used in

Docusaurus, ESLint, FormKit, Histoire, Knip, Nitro, Nuxt, PostCSS loader, Rsbuild, Size Limit, Slidev, Tailwindcss, Tokenami, UnoCSS, WXT, Winglang, Graphql code generator, Lingui, Scaffdog, Storybook, ...UnJS ecosystem, ...60M+ npm monthly downloads, ...6M+ public repositories.

✅ Features

• Seamless TypeScript and ESM syntax support for Node.js
• Seamless interoperability between ESM and CommonJS
• Asynchronous API to replace import()
• Synchronous API to replace require() (deprecated)
• Super slim and zero dependency
• Custom resolve aliases
• Smart syntax detection to avoid extra transforms
• Node.js native require.cache integration
• Filesystem transpile with hard disk caches
• ESM Loader support
• JSX support (opt-in)

[!IMPORTANT] To enhance compatibility, jiti >=2.1 enabled interopDefault using a new Proxy method. If you migrated to 2.0.0 earlier, this might have caused behavior changes. In case of any issues during the upgrade, please report so we can investigate to solve them. 🙏🏼

💡 Usage

CLI

You can use jiti CLI to quickly run any script with TypeScript and native ESM support!

npx jiti ./index.ts

Programmatic

Initialize a jiti instance:

// ESM
import { createJiti } from "jiti";
const jiti = createJiti(import.meta.url);

// CommonJS (deprecated)
const { createJiti } = require("jiti");
const jiti = createJiti(__filename);

Import (async) and resolve with ESM compatibility:

// jiti.import(id) is similar to import(id)
const mod = await jiti.import("./path/to/file.ts");

// jiti.esmResolve(id) is similar to import.meta.resolve(id)
const resolvedPath = jiti.esmResolve("./src");

If you need the default export of module, you can use jiti.import(id, { default: true }) as shortcut to mod?.default ?? mod.

// shortcut to mod?.default ?? mod
const modDefault = await jiti.import("./path/to/file.ts", { default: true });

CommonJS (sync & deprecated):

// jiti() is similar to require(id)
const mod = jiti("./path/to/file.ts");

// jiti.resolve() is similar to require.resolve(id)
const resolvedPath = jiti.resolve("./src");

You can also pass options as the second argument:

const jiti = createJiti(import.meta.url, { debug: true });

Register global ESM loader

You can globally register jiti using global hooks. (Important: Requires Node.js > 20)

import "jiti/register";

Or:

node --import jiti/register index.ts

🎈 jiti/native

You can alias jiti to jiti/native to directly depend on runtime's import.meta.resolve and dynamic import() support. This allows easing up the ecosystem transition to runtime native support by giving the same API of jiti.

⚙️ Options

debug

• Type: Boolean
• Default: false
• Environment variable: JITI_DEBUG

Enable verbose logging. You can use JITI_DEBUG=1 <your command> to enable it.

fsCache

• Type: Boolean | String
• Default: true
• Environment variable: JITI_FS_CACHE

Filesystem source cache (enabled by default)

By default (when is true), jiti uses node_modules/.cache/jiti (if exists) or {TMP_DIR}/jiti.

Note: It is recommended that this option be enabled for better performance.

rebuildFsCache

• Type: Boolean
• Default: false
• Environment variable: JITI_REBUILD_FS_CACHE

Rebuild filesystem source cache created by fsCache.

moduleCache

• Type: String
• Default: true
• Environment variable: JITI_MODULE_CACHE

Runtime module cache (enabled by default).

Disabling allows editing code and importing the same module multiple times.

When enabled, jiti integrates with Node.js native CommonJS cache-store.

transform

• Type: Function
• Default: Babel (lazy loaded)

Transform function. See src/babel for more details

sourceMaps

• Type: Boolean
• Default false
• Environment variable: JITI_SOURCE_MAPS

Add inline source map to transformed source for better debugging.

interopDefault

• Type: Boolean
• Default: true
• Environment variable: JITI_INTEROP_DEFAULT

Jiti combines module exports with the default export using an internal Proxy to improve compatibility with mixed CJS/ESM usage. You can check the current implementation here.

[!WARNING] This option wraps all imported modules in a Proxy, which adds ~25-50ns overhead per property access. For performance-critical hot paths where you access module exports very frequently, consider setting interopDefault: false or JITI_INTEROP_DEFAULT=false.

alias

• Type: Object
• Default: -
• Environment variable: JITI_ALIAS

You can also pass an object to the environment variable for inline config. Example: JITI_ALIAS='{"~/*": "./src/*"}' jiti ....

Custom alias map used to resolve IDs.

tsconfigPaths

• Type: Boolean | String
• Default: false
• Environment variable: JITI_TSCONFIG_PATHS

Enable TypeScript paths resolution using get-tsconfig.

• true: Auto-discover tsconfig.json by walking up from the jiti instance's parent path.
• string: Explicit path to a tsconfig.json file.
• false (default): Disabled.

nativeModules

• Type: Array
• Default: ['typescript']
• Environment variable: JITI_NATIVE_MODULES

List of modules (within node_modules) to always use native require() for them.

transformModules

• Type: Array
• Default: []
• Environment variable: JITI_TRANSFORM_MODULES

List of modules (within node_modules) to transform them regardless of syntax.

importMeta

Parent module's import.meta context to use for ESM resolution. (only used for jiti/native import).

tryNative

• Type: Boolean
• Default: Enabled if bun is detected
• Environment variable: JITI_TRY_NATIVE

Try to use native require and import without jiti transformations first.

jsx

• Type: Boolean | {options}
• Default: false
• Environment Variable: JITI_JSX

Enable JSX support using @babel/plugin-transform-react-jsx.

See test/fixtures/jsx for framework integration examples.

Development

• Clone this repository
• Enable Corepack using corepack enable
• Install dependencies using pnpm install
• Run pnpm dev
• Run pnpm jiti ./test/path/to/file.ts

License

Published under the MIT license. Made by @pi0 and community 💛