The jiti npm package is a runtime TypeScript and ES Module (ESM) loader that allows you to import TypeScript files, ESM, or JSON modules dynamically in a Node.js environment without the need for prior compilation. It is designed to be a zero-config, drop-in replacement for dynamic imports and require calls, providing just-in-time transpilation of code.
Dynamic Import of TypeScript Files
This feature allows you to dynamically import TypeScript files at runtime. The jiti function is called with the current filename to create a context, and then it is used to import a TypeScript module, which is transpiled just-in-time.
const jiti = require('jiti')(__filename)
const myModule = jiti('./my-module.ts')Dynamic Import of ESM
With this feature, jiti can dynamically import ES Module files. The 'esmResolve' option enables proper resolution of ESM modules, allowing them to be loaded at runtime without prior compilation.
const jiti = require('jiti')(__filename, { esmResolve: true })
const myESMModule = jiti('./my-esm-module.mjs')Dynamic Import of JSON Modules
This feature enables the dynamic import of JSON modules. By using jiti, you can load JSON files at runtime, which can be useful for configuration files or other data that needs to be imported into your application.
const jiti = require('jiti')(__filename)
const config = jiti('./config.json')esbuild-register is a package that uses the esbuild bundler to transpile TypeScript and modern JavaScript on the fly for Node.js. It is similar to jiti in that it allows just-in-time transpilation, but it leverages the fast esbuild compiler.
ts-node is a TypeScript execution engine and REPL for Node.js. It provides on-the-fly transpilation of TypeScript into JavaScript, allowing developers to execute TypeScript directly without pre-compilation. ts-node is widely used and has more configuration options compared to jiti.
babel-register is a Babel hook that transpiles files on the fly when they are required. It is similar to jiti in providing just-in-time transpilation, but it uses Babel, which has a wide range of plugins and is highly configurable.
This is the active development branch. Check out jiti/v1 for legacy v1 docs and code.
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.
import()require() (deprecated)require.cache integration[!IMPORTANT] To enhance compatibility, jiti
>=2.1enabledinteropdefaultusing a new Proxy method. If you migrated to2.0.0earlier, this might have caused behavior changes. In case of any issues during the upgrade, please report so we can investigate to solve them. 🙏🏼
You can use jiti CLI to quickly run any script with TypeScript and native ESM support!
npx jiti ./index.ts
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 });
You can globally register jiti using global hooks. (Important: Requires Node.js > 20)
import "jiti/register";
Or:
node --import jiti/register index.ts
jiti/nativeYou 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.
debugfalseJITI_DEBUGEnable verbose logging. You can use JITI_DEBUG=1 <your command> to enable it.
fsCachetrueJITI_FS_CACHEFilesystem 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.
moduleCachetrueJITI_MODULE_CACHERuntime 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.
transformTransform function. See src/babel for more details
sourceMapsfalseJITI_SOURCE_MAPSAdd inline source map to transformed source for better debugging.
interopDefaulttrueJITI_INTEROP_DEFAULTJiti 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.
aliasJITI_ALIASYou can also pass an object to the environment variable for inline config. Example: JITI_ALIAS='{"~/*": "./src/*"}' jiti ....
Custom alias map used to resolve IDs.
nativeModulesJITI_NATIVE_MODULESList of modules (within node_modules) to always use native require() for them.
transformModulesJITI_TRANSFORM_MODULESList of modules (within node_modules) to transform them regardless of syntax.
importMetaParent module's import.meta context to use for ESM resolution. (only used for jiti/native import).
tryNativeJITI_TRY_NATIVETry to use native require and import without jiti transformations first.
jsxfalseJITI_JSXEnable JSX support using @babel/plugin-transform-react-jsx.
See test/fixtures/jsx for framework integration examples.
corepack enablepnpm installpnpm devpnpm jiti ./test/path/to/file.tsPublished under the MIT license.
Made by @pi0 and community 💛
FAQs
Runtime typescript and ESM support for Node.js
The npm package jiti receives a total of 16,936,812 weekly downloads. As such, jiti popularity was classified as popular.
We found that jiti demonstrated a healthy version release cadence and project activity because the last version was released less than a year ago. It has 1 open source maintainer collaborating on the project.
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