@babel/node

babel-node is a CLI that works exactly the same as the Node.js CLI, with the added benefit of compiling with Babel presets and plugins before running it.

Install

npm

npm install --save-dev @babel/core @babel/node

Yarn

yarn add --dev @babel/core @babel/node

pnpm

pnpm add --save-dev @babel/core @babel/node

caution

Not meant for production use

You should not be using babel-node in production. It is unnecessarily heavy, with high memory usage due to the cache being stored in memory. You will also always experience a startup performance penalty as the entire app needs to be compiled on the fly.

Check out the example Node.js server with Babel for an idea of how to use Babel in a production deployment.

ES6-style module-loading may not function as expected

Due to technical limitations ES6-style module-loading is not fully supported in a babel-node REPL.

babel comes with a second CLI which works exactly the same as Node.js's CLI, only it will compile ES6 code before running it.

Launch a REPL (Read-Eval-Print-Loop).

note

You should install @babel/node and @babel/core first before npx babel-node, otherwise npx will install out-of-dated legacy babel-node 6.x.

Shell

npx babel-node

If you prefer not to install @babel/node and @babel/core, you can install them on-the-fly:

Shell

npx -p @babel/core -p @babel/node babel-node

Evaluate code.

Shell

npx babel-node -e "class Test { }"

Compile and run test.js.

Shell

npx babel-node test

tip

Use rlwrap to get a REPL with input history

Shell

rlwrap npx babel-node

On some platforms (like OSX), extra arguments may be required for rlwrap to function properly, eg:

Shell

NODE_NO_READLINE=1 rlwrap --always-readline npx babel-node

Usage

Shell

babel-node [options] [ -e script | [--] script.js ] [arguments]

When arguments for user script have names conflicting with node options, double dash placed before script name can be used to resolve ambiguities

Shell

npx babel-node --inspect --presets @babel/preset-env -- script.js --inspect

Options

Option	Default	Description
-e, --eval [script]		Evaluate script
-p, --print		Evaluate script and print result
-i, --ignore [regex]	node_modules	Ignore all files that match this regex when using the require hook. If both -i and -o are omitted, files outside the current working directory are also ignored.
-o, --only [regex]	current working directory	Only include (and exclude all other) files that match this regex when using the require hook. If both -i and -o are omitted, files outside the current working directory are also ignored.
-x, --extensions	".js",".jsx",".es6",".es","cjs"	List of extensions to hook into
--presets	[]	Comma-separated list of presets (a set of plugins) to load and use.
--plugins	[]	Comma-separated list of plugins to load and use.
--config-file [path]	[]	Path to the babel config file to use. Defaults to working directory babel.config.json or babel.config.js. The following options in config files are not supported: ignore, only.
--env-name [name]	[]	The name of the 'env' to use when loading configs and plugins. Defaults to the value of BABEL_ENV, or else NODE_ENV, or else 'development'.