preact-material-components/docs/node_modules/preact-cli/babel/index.js

preact wrapper for "Material Components for the web"

var isProd = (process.env.BABEL_ENV || process.env.NODE_ENV) === "production";
/**
 * test env detection is used to default mode for
 * preset-env modules to "commonjs" otherwise, testing framework
 * will struggle
 */
var isTest = (process.env.BABEL_ENV || process.env.NODE_ENV) === "test";

// default supported browser.
var defaultBrowserList = ["> 1%", "last 2 versions", "IE >= 9"];

// preact-cli babel configs
var babelConfigs = require("./../lib/lib/babel-config").default;

/**
 * preset as a function means allow users to override some options
 * like env, modules for environment
 */
module.exports = function preactCli(ctx, userOptions = {}) {

	// set default configs based on user environment
	var presetOptions = {
		env: isProd ? "production" : "development",
		modules: isTest ? "commonjs" : false,
		browsers: defaultBrowserList
	};

	// user specified options always the strongest
	Object.keys(presetOptions).forEach(function (key) {
		presetOptions[key] = userOptions[key] || presetOptions[key];
	});

	// yay! return the configs
	return babelConfigs(
		{ env: { production: presetOptions.env === "production" } },
		{ modules: presetOptions.modules, browsers: presetOptions.browsers }
	);
};