Options for babel transpiling.


babel.transform(code, options);
$ babel --name=value


Option Default Description
filename "unknown" Filename for use in errors etc.
filenameRelative (filename) Filename relative to sourceRoot.
blacklist [] Array of transformers to exclude. Run babel --help to see a full list of transformers.
whitelist [] Array of transformers to only use. Run babel --help to see a full list of transformers.
loose [] Array of transformers to enable loose mode on.
optional [] Array of transformers to optionally use. Run babel --help to see a full list of transformers. Optional transformers displayed inside square brackets.
nonStandard true Enable support for JSX and Flow.
highlightCode true ANSI highlight syntax error code frames
only null A glob, regex, or mixed array of both, matching paths to only compile. Can also be an array of arrays containing paths to explicitly match. When attempting to compile a non-matching file it's returned verbatim.
ignore null Opposite to the only option.
jsxPragma null Custom pragma to use for JSX elements
auxiliaryCommentBefore null Attach a comment before all helper declarations and auxiliary code. eg. "istanbul ignore next"
sourceMaps false If truthy, adds a map property to returned output. If set to "inline", a comment with a sourceMappingURL directive is added to the bottom of the returned code. If set to "both" then a map property is returned as well as a source map comment appended.
inputSourceMap null A source map object that the output source map will be based on.
sourceMapTarget (filenameRelative) Set file on returned source map.
sourceFileName (filenameRelative) Set sources[0] on returned source map.
sourceRoot (moduleRoot) The root from which all sources are relative.
moduleRoot (sourceRoot) Optional prefix for the AMD module formatter that will be prepend to the filename on module definitions.
modules "common" Which module formatter to use. Run babel --help to see a full list of module formatters.
moduleIds false If truthy, insert an explicit id for modules. By default, all modules are anonymous. (Not available for common modules)
moduleId null Specify a custom name for module ids.
getModuleId null Specify a custom callback to generate a module id with. Called as getModuleId(moduleName). If falsy value is returned then the generated module id is used.
resolveModuleSource null Resolve a module source ie. import "SOURCE"; to a custom value. Called as resolveModuleSource(source, filename).
keepModuleIdExtensions false Keep extensions in module ids
externalHelpers false Uses a reference to babelHelpers instead of placing helpers at the top of your code. Meant to be used in conjunction with external helpers.
code true Enable code generation
ast true Include the AST in the returned object
stage 2 Set the experimental proposal stage.
compact "auto" Do not include superfluous whitespace characters and line terminators. When set to "auto" compact is set to true on input sizes of >100KB.
comments true Output comments in generated output.
shouldPrintComment null An optional callback that controls whether a comment should be output or not. Called as shouldPrintComment(commentContents). NOTE: This overrides the comment option when used.
metadataUsedHelpers false See external helpers - selective builds for more information.
env {}

This is an object of keys that represent different environments. For example, you may have:

{ env: { production: { /* specific options */ } } }`

which will use those options when the enviroment variable BABEL_ENV is set to "production". If BABEL_ENV isn't set then NODE_ENV will be used, if it's not set then it defaults to "development"

retainLines false

Retain line numbers. This will lead to wacky code but is handy for scenarios where you can't use source maps.

NOTE: This will obviously not retain the columns.
babelrc null Specify a custom file path to load a .babelrc config from.