babel-preset

This Babel 7 preset transpiles ES2020, JSX, and selected language proposals. It also includes optimizations for specific contexts.

Install

$ npm install -D @kensho-technologies/babel-preset

Usage

You can set up Babel transpilation in several ways. Choose a method, and configure Babel to include the preset, e.g. in a babel.config.json:

{
  "presets": ["@kensho-technologies/babel-preset"]
}

Options

The preset can be configured using several options. Note that some options' defaults depend on the Babel environment, which may be one of the following:

Environment	Purpose
development	Transpiling an app for development.
production	Transpiling an app for production.
test	Transpiling an app or library to run in the current version of Node.
cjs	Transpiling a library for distribution as CJS.
esm	Transpiling a library for distribution as ESM.

The present extends @babel/preset-env, and forwards all additional options to that preset.

emotion

false | options
Default: false

Whether to enable support for CSS-in-JS via Emotion. If an options object is passed, it is forwarded to the Emotion plugin. This option requires an additional dependency on @emotion/react.

modules

false | 'commonjs'
Default: 'commonjs' in test and cjs envs, false otherwise

Whether to compile ESM imports/exports to another module format.

// false:
import foo from './foo'

// 'commonjs' (roughly):
const foo = require('./foo')

react

false | options
Default: {}

Whether to transpile JSX expressions. If an options object is passed, it is forwarded to the React preset.

reactRefresh

false | options
Default: {} in development env if react is enabled

Whether to transform React function components for fast refresh. If an options object is passed, it is forwarded to the React Refresh plugin. The list of available options is not currently documented.

This option should only ever be enabled in development. It also requires bundler integration because the output code references global variables containing the Refresh runtime. If this integration cannot be added to a project's development environment, this option should be disabled.

runtime

true | false
Default: true

Whether to enable the Babel runtime transform. This is encouraged to reduce bundle size, but requires adding @babel/runtime as a dependency.

targets

See @babel/preset-env options documentation.
Default: current node version in test environment, inferred from browserslist config otherwise

The transpilation targets to pass to @babel/preset-env.

typescript

false | options
Default: {}

Whether to enable TypeScript support. If an options object is passed, it's passed to the TypeScript preset.

License

Licensed under the Apache 2.0 License. Unless required by applicable law or agreed to in writing, software distributed under the License is distributed on an "AS IS" BASIS, WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied. See the License for the specific language governing permissions and limitations under the License.

Copyright 2020-present Kensho Technologies, LLC. The present date is determined by the timestamp of the most recent commit in the repository.