lib/process_babel_plugins.js
function isBuiltinPlugin(name) {
	var isNpmPluginName = /^(?:babel-plugin-)/;
	var availablePlugins = babel.availablePlugins;

	// if the full npm plugin name was set in `babelOptions.plugins`, use the
	// shorthand to check whether the plugin is included in babel-standalone;
	// shorthand plugin names are used internally by babel-standalone
	var shorthand = isNpmPluginName.test(name) ?
		name.replace("babel-plugin-", "") :
		name;

	return !!availablePlugins[shorthand];
}
function isBuiltinPlugin(name) {
	var isNpmPluginName = /^(?:babel-plugin-)/;
	var availablePlugins = babel.availablePlugins;

	// if the full npm plugin name was set in `babelOptions.plugins`, use the
	// shorthand to check whether the plugin is included in babel-standalone;
	// shorthand plugin names are used internally by babel-standalone
	var shorthand = isNpmPluginName.test(name) ?
		name.replace("babel-plugin-", "") :
		name;

	return !!availablePlugins[shorthand];
}
function isBuiltinPlugin ( name ) { var isNpmPluginName = / ^(?:babel-plugin-) / ; var availablePlugins = babel . availablePlugins ; // if the full npm plugin name was set in `babelOptions.plugins`, use the // shorthand to check whether the plugin is included in babel-standalone; // shorthand plugin names are used internally by babel-standalone var shorthand = isNpmPluginName . test ( name ) ? name . replace ( "babel-plugin-" , "" ) : name ; return ! ! availablePlugins [ shorthand ] ; }
Whether the plugin is built in babel-standalone

@param {string} name A plugin path or shorthand name.
@return {boolean} `true` if plugin is bundled, `false` otherwise

Babel plugins can be set using the following variations:

1) the npm plugin name, which by convention starts with `babel-plugin-`
(e.g babel-plugin-transform-decorators).
2) A shorthand name, which is the npm name without the `babel-plugin-` prefix
3) A path to where the plugin function is defined

babel-standalone registers the plugins bundled with it using the shorthand
version.
Whether the plugin is built in babel - standalone