NodeJS - 解析JSON（只有字符串或数字） - 编程

I have got a little dilema what to do (What should I do). I've got in my app several places where I am using AJAX to transfer a JSON data. So for example receiving a data from the registration form:

我有一点困境做什么(我该怎么办)。我在我的应用程序中有几个地方,我使用AJAX传输JSON数据。例如,从注册表中接收数据:

try {
   var data = JSON.parse(json);
}
catch(e) {
   // ...
}

var fields = {
   firstName: data.firstName || "",
   lastName: data.lastName || "",
   ...
};

Then I need to do something with these fields. Let's say:

然后我需要对这些领域做点什么。让我们说:

if (fields.firstName) {
   // OK save it to the DB
}

if(fields.lastName.xxx()) { // xxx() is a method that belongs to JS String Object
   // Do something...
}

The problem is what if fields.firstName or fields.lastName is {} / []? That may happen if somebody sent a modified JSON with a wrong data types, the whole app will then crash since the method xxx is missing.

问题是如果fields.firstName或fields.lastName是{} / []?如果有人发送了带有错误数据类型的修改后的JSON,那么可能会发生这种情况,整个应用程序将因为缺少方法xxx而崩溃。

Do I have to check the type of every field whether it is really a string, a number, an array... or is there some another maybe nicer way how to do this?

我是否必须检查每个字段的类型是否真的是一个字符串,一个数字,一个数组......还是有另外一个可能更好的方法如何做到这一点?

3 个解决方案

#1

Unfortunately that's a problem you'll have to face anytime using a dynamic language like JavaScript.

不幸的是,使用动态语言(如JavaScript)时,您将不得不面对这个问题。

One possible solution is not using String methods, but creating a function that will check it's arguments first:

一种可能的解决方案是不使用String方法,而是创建一个首先检查它的参数的函数:

// original, with string methods
if (text instanceof String && text.trim().length === 0) { ... }

// alternative, define function first
var isEmptyString = function(text) {
  if (!(text instanceof String)) throw new Error("Argument must be a String");
  return text.trim().length === 0;
}

// use it in your code
if (isEmptyString(text)) { ... }

That can lead to cleaner code. Just be sure not to define those functions in a global scope, when you have to use them in a Browser. Within the node.js modules that should not be a problem.

这可以使代码更清晰。当您必须在浏览器中使用它们时,请确保不要在全局范围内定义这些函数。在node.js模块中应该不是问题。

NodeJS - 解析JSON（只有字符串或数字）

3 个解决方案

#1

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