exports.getDefaults = function getDefaults(features) {
  var options = {
    compact: false,
    sourceMap: "inline",
    ast: false,
    babelrc: false,
    // "Loose" mode gets us faster and more IE-compatible transpilations of:
    // classes, computed properties, modules, for-of, and template literals.
    // Basically all the transformers that support "loose".
    // http://babeljs.io/docs/usage/loose/
    presets: [require("babel-preset-meteor")],
    plugins: []
  };

  if (features) {
    if (features.react) {
      options.presets.push(
        require("babel-preset-react")
      );
    }

    if (features.jscript) {
      options.plugins.push(
        require("./plugins/named-function-expressions.js"),
        require("./plugins/sanitize-for-in-objects.js")
      );
    }

    if (features.legacyModules) {
      options.plugins.push(
        require("babel-plugin-transform-es2015-modules-commonjs")
      );
    }
  }

  return options;
};

@@ -1,8 +1,732 @@
+var strictModulesPluginFactory =%0A  require(%22babel-plugin-transform-es2015-modules-commonjs%22);%0A%0Avar babelModulesPlugin = %5Bfunction () %7B%0A  var plugin = strictModulesPluginFactory.apply(this, arguments);%0A  // Since babel-preset-meteor uses an exact version of the%0A  // babel-plugin-transform-es2015-modules-commonjs transform (6.8.0), we%0A  // can be sure this plugin.inherits property is indeed the%0A  // babel-plugin-transform-strict-mode transform that we wish to disable.%0A  // Otherwise it would be difficult to know exactly what we're deleting%0A  // here, since plugins don't provide much identifying information.%0A  delete plugin.inherits;%0A  return plugin;%0A%7D, %7B%0A  allowTopLevelThis: true,%0A  strict: false,%0A  loose: true%0A%7D%5D;%0A%0A
 exports.
@@ -1576,81 +1576,26 @@
 ush(
-%0A        require(%22babel-plugin-transform-es2015-modules-commonjs%22)%0A      
+babelModulesPlugin
 );%0A 

Make legacy modules non-strict, as in Meteor versions < 1.3.3.