JavaScript needs modules(blog.mozilla.com)

  module A {
    export var myPublic = 1
    var myPrivate = 2
  }

  var A = new function() {
    this.myPublic = 1
    var myPrivate = 2
  }

    myModule: {
      // don't do anything if myModule is already included
      if (myModule) break myModule;
      
      let this_is_private = ...;
      var myModule = ...;
      // myModule is public and won't pollute the
      // global NS if it isn't included globally.
    }