Consider adding a module level visibility modifier.

还没有人认领这个 Issue。

Currently to protect integrity of data one can only use classes with private or protected fields. Classes are harder to work with compared to object literals. Being able to specify that certain fields are invisible to outside modules would be a valuable addition to support programming in functional style in TypeScript.

So what I am suggesting is to be able to specify whether a field of an interface is exported from a module or not. This also means that the instance of such interface can only be created within the module it is declared.

The similar features can be found in:
- F# called `signature files`: http://msdn.microsoft.com/en-us/library/dd233196.aspx
- Haskell called `export lists`: http://www.haskell.org/onlinereport/modules.html

首先审查所提议的模块级可见性行为，以及所引用的 F# 签名文件和 Haskell 导出列表。确定预期的接口语法、模块边界，以及可以如何创建实例。当设计已解决，并且行为已得到足够详细的规范以供实现和测试时，即视为完成。

由索引模型根据 Issue 内容生成。