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babel-node
@babel/node
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 install --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. :::

npx babel-node

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

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

Evaluate code.

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

Compile and run test.js.

npx babel-node test

:::tip Use rlwrap to get a REPL with input history

rlwrap npx babel-node

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

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

:::

Usage

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

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'.