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.
Runtime typescript and ESM support for Node.js (CommonJS)
const jiti = require('jiti')(__filename)
jiti('./path/to/file.ts')
You can also pass options as second argument:
const jiti = require('jiti')(__filename, { debug: true })
jiti index.ts
# or npx jiti index.ts
node -r jiti/register index.ts
Alternatively, you can register jiti as a require hook programmatically:
const jiti = require('jiti')()
const unregister = jiti.register()
debugfalseJITI_DEBUGEnable debug to see which files are transpiled
cachetrueJITI_CACHEUse transpile cache
If set to true will use node_modules/.cache/jiti (if exists) or {TMP_DIR}/node-jiti
transformTransform function. See src/babel for more details
standard-things/esm+ Much more stable thanks to babel+ Less low level operations+ Typescript support- Slower (without cache)babel-register+ Smaller install size (~1M vs ~11M with same plugins)+ Configured out of the box+ Smart syntax detect to avoid unnecessary transpilation+ Does not ignores node_modules. ESM everywhere yay!+ Embeddableesbuild+ No native dependency+ More stable thanks to babel- Slower+ Embeddablets-node+ Support both esm and typescript/ No typechecking support / Faster+ Smart syntax detect to avoid unnecessary transpilation.mjs files with different executation context (no __filename, require, etc)rollup, webpack, snowpack, etc)Meanwhile it would be much better making an optimized bundle to deploy to production or as npm package, using bundler setup and watching is frustrating during project development that's where jiti (or similar tools like ts-node) would be more convenient.
Note: However currently only babel transform is supported, configurable transform support is in the roadmap so using esbuild or other solutions would be possible.
yarnyarn buildyarn devnode ./test/jiti.jsnode -r jitiMIT. Made with 💖
1.5.0 (2021-03-03)
extensions option (fixes mjs handling) (3804b3c)FAQs
Runtime typescript and ESM support for Node.js
The npm package jiti receives a total of 8,277,407 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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