babel-plugin-feature-flags
This plugin is for Babel 6. If you need to support Babel 5 use the 0.2.x releases.
A babel plugin that implements feature flags for enabling and disabling features. This plugin is intended to be followed by a dead code elimination pass (Uglify, babel-plugin-dead-code-elimination, etc.) to remove any unreachable code.
Feature flags are implemented by looking for call expressions like isEnabled('my-feature')
and checking if the feature is enabled/disabled/disabled in a feature map that is passed through the plugin options. If the feature is known to be enabled or disabled then the call expression is replace with a boolean literal (true
or false
respectively). If the feature is dynamic, than the call expression is left alone.
Example
Given the .babelrc
the JavaScript file
; if // code
will be transformed to
; if false // code
Configuration
Here are the options that you can pass to the babel plugin.
options.import.module
[String
]: The name of the module that the feature function is imported from.options.import.name
[String
(Optional)]: The name of the export that the feature function is imported from. Defaults to"default"
.options.features
[Map(String -> 'enabled' | 'disabled' | 'dynamic')
]: An object whose keys are the names of features and whose values determine whether the feature is enabled/disabled/dynamic.