如何编写健壮的 TypeScript 库？

{"type":"doc","content":[{"type":"paragraph","attrs":{"indent":0,"number":0,"align":null,"origin":null},"content":[{"type":"text","text":"当你用 TypeScript 编写库时，你通常不知道这个库最终将如何被使用。即使你 警告潜在用户，你编写这个库只是针对 TypeScript 用户，你还是可能会在某个时刻拥有 JavaScript 用户——或者是因为他们不顾你的警告而使用这个库，或者是他们因为传递性依赖而使用这个库。这有一个非常重要的后果：你必须将这个库设计成任何语言的开发者都可以使用！"}]},{"type":"paragraph","attrs":{"indent":0,"number":0,"align":null,"origin":null}},{"type":"paragraph","attrs":{"indent":0,"number":0,"align":null,"origin":null},"content":[{"type":"text","text":"其主要部分是函数定义和函数体。如果你针对一个纯 TypeScript 读者编写，那么你只需定义函数类型并信任编译器处理其它事情。如果你针对一个纯 JavaScrpit 读者编写，那么你需要记录那些类型，但在函数中将实际的类型设为"},{"type":"codeinline","content":[{"type":"text","text":"unknown"}]},{"type":"text","text":"并检查调用方传递的内容。"}]},{"type":"paragraph","attrs":{"indent":0,"number":0,"align":null,"origin":null}},{"type":"paragraph","attrs":{"indent":0,"number":0,"align":null,"origin":null},"content":[{"type":"text","text":"例如，给定如下代码"}]},{"type":"paragraph","attrs":{"indent":0,"number":0,"align":null,"origin":null}},{"type":"bulletedlist"},{"type":"paragraph","attrs":{"indent":0,"number":0,"align":null,"origin":null}},{"type":"codeblock","attrs":{"lang":"text"},"content":[{"type":"text","text":"interface Person {"}]},{"type":"paragraph","attrs":{"indent":0,"number":0,"align":null,"origin":null}},{"type":"paragraph","attrs":{"indent":0,"number":0,"align":null,"origin":null},"content":[{"type":"text","text":"一个 JS 用户可能用任何东西来调用"},{"type":"codeinline","content":[{"type":"text","text":"describe"}]},{"type":"text","text":"函数。"}]},{"type":"paragraph","attrs":{"indent":0,"number":0,"align":null,"origin":null}},{"type":"paragraph","attrs":{"indent":0,"number":0,"align":null,"origin":null},"content":[{"type":"text","text":"正确写法："}]},{"type":"paragraph","attrs":{"indent":0,"number":0,"align":null,"origin":null}},{"type":"bulletedlist"},{"type":"paragraph","attrs":{"indent":0,"number":0,"align":null,"origin":null}},{"type":"codeblock","attrs":{"lang":"text"},"content":[{"type":"text","text":"describe({ name: \"chris\" })"}]},{"type":"paragraph","attrs":{"indent":0,"number":0,"align":null,"origin":null}},{"type":"bulletedlist"},{"type":"paragraph","attrs":{"indent":0,"number":0,"align":null,"origin":null},"content":[{"type":"text","text":"灾难性的错误写法："}]},{"type":"codeblock","attrs":{"lang":"text"},"content":[{"type":"text","text":"describe(\"potato\");"}]},{"type":"paragraph","attrs":{"indent":0,"number":0,"align":null,"origin":null},"content":[{"type":"text","text":"最常见的 JS 错误:"}]},{"type":"bulletedlist"},{"type":"paragraph","attrs":{"indent":0,"number":0,"align":null,"origin":null}},{"type":"codeblock","attrs":{"lang":"text"},"content":[{"type":"text","text":"describe(undefined);"}]},{"type":"paragraph","attrs":{"indent":0,"number":0,"align":null,"origin":null},"content":[{"type":"text","text":"你的库的 JS 用户并不是故意这么做的。恰恰相反，在任何足够大的系统中，很容易将错误的参数传递给系统中的某个函数。这通常是一个很难避免的错误，比如在一个点上做了修改，许多其它地方需要更新，但漏掉了一个点。故意的 JS 开发者会把坏数据发送到你设计精美的 TS API 中。"}]},{"type":"paragraph","attrs":{"indent":0,"number":0,"align":null,"origin":null}},{"type":"blockquote","content":[{"type":"paragraph","attrs":{"indent":0,"number":0,"align":null,"origin":null},"content":[{"type":"text","text":"如果你针对一个纯 TypeScript 读者编写，那么你只需定义函数类型并信任编译器处理其它事情"}]}]},{"type":"paragraph","attrs":{"indent":0,"number":0,"align":null,"origin":null}}]}