@babel/cli

Babel comes with a built-in CLI which can be used to compile files from the command line.

The main Babel CLI script, babel.js, lives in the top-level package at @babel/cli/bin.

Install

While you can install Babel CLI globally on your machine, it's much better to install it locally project by project.

There are two primary reasons for this.

1. Different projects on the same machine can depend on different versions of Babel allowing you to update them individually.
2. Not having an implicit dependency on the environment you are working in makes your project far more portable and easier to setup.

We can install Babel CLI locally by running:

npm

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

Yarn

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

pnpm

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

Bun

bun add --dev @babel/core @babel/cli

note

If you do not have a package.json, create one before installing. This will ensure proper interaction with the npx command.

After that finishes installing, your package.json file should include:

{
  "devDependencies": {
+   "@babel/cli": "^8.0.0",
+   "@babel/core": "^8.0.0"
  }
}

Usage

note

Please install @babel/cli and @babel/core first before npx babel, otherwise npx will install out-of-dated babel 6.x. Other than npx, you can also drop it inside of an npm run script or you may instead execute with the relative path instead. ./node_modules/.bin/babel

Shell

npx babel script.js

Print Usage

Shell

npx babel --help

Compile Files

Compile the file script.js and output to stdout.

Shell

npx babel script.js
# output...

If you would like to output to a file you may use --out-file or -o.

Shell

npx babel script.js --out-file script-compiled.js

To compile a file every time that you change it, use the --watch or -w option:

Shell

npx babel script.js --watch --out-file script-compiled.js

Compile with Source Maps

note

Since v7.19.3, if this parameter is not specified, @babel/cli will follow the configuration files.

If you would then like to add a source map file you can use --source-maps or -s.

Shell

npx babel script.js --out-file script-compiled.js --source-maps

Or, if you'd rather have inline source maps, use --source-maps inline instead.

Shell

npx babel script.js --out-file script-compiled.js --source-maps inline

Compile Directories

Compile the entire src directory and output it to the lib directory by using either --out-dir or -d. This doesn't overwrite any other files or directories in lib.

Shell

npx babel src --out-dir lib

Compile the entire src directory and output it as a single concatenated file.

Shell

npx babel src --out-file script-compiled.js

Directories with TypeScript Files

Use the --extensions option to specify what file extensions Babel should handle when compiling the entire src directory. The default --extensions can be accessed from Babel.DEFAULT_EXTENSIONS.

Shell

npx babel src --out-dir lib \
  --extensions .ts,.js,.tsx,.jsx,.cjs,.mjs \
  --presets=@babel/preset-typescript,@babel/preset-env,@babel/preset-react

Ignore files

Ignore spec and test files

Shell

npx babel src --out-dir lib --ignore "src/**/*.spec.js","src/**/*.test.js"

Copy files

Copy files that will not be compiled

Shell

npx babel src --out-dir lib --copy-files

If you don't want to copy ignored JavaScript files:

History

Version	Changes
v7.8.0	Added --copy-ignored
v7.8.4	Change copyeIgnored option default to true, it can be disabled by --no-copy-ignored

Shell

npx babel src --out-dir lib --copy-files --no-copy-ignored

Piping Files

Pipe a file in via stdin and output it to script-compiled.js

Shell

npx babel --out-file script-compiled.js < script.js

Using Plugins

Use the --plugins option to specify plugins to use in compilation

Shell

npx babel script.js --out-file script-compiled.js --plugins=@babel/transform-class-properties,@babel/transform-modules-amd

Using Presets

Use the --presets option to specify presets to use in compilation

Shell

npx babel script.js --out-file script-compiled.js --presets=@babel/preset-env,@babel/flow

Using Config Files

Ignoring .babelrc.json or .babelrc

Ignore the configuration from the project's .babelrc or .babelrc.json file and use the cli options e.g. for a custom build

Shell

npx babel --no-babelrc script.js --out-file script-compiled.js --presets=@babel/preset-env,@babel/preset-react

Custom config path

Shell

npx babel --config-file /path/to/my/babel.config.json --out-dir dist ./src

See here for more information about config files.

Set File Extensions

Added in: v7.8.0

By default, the transpiled file will use the .js extension.

You can control the output file extension with --out-file-extension

Shell

npx babel src --out-dir lib --out-file-extension .mjs

You can also preserve the input file extension with --keep-file-extension

Shell

npx babel src-with-mjs-and-cjs --out-dir lib --keep-file-extension

Note that --keep-file-extension and --out-file-extension cannot be used together.

Output levels

History

Version	Changes
v7.7.0	Added --silent

Shell

# Log everything to stdout
npx babel script.js --out-file script-compiled.js --verbose

# Mute the "Successfully compiled..." log
npx babel script.js --out-file script-compiled.js --silent

Advanced Usage

There are many more options available, see options, babel --help and other sections for more information.