从半动态JSON文件中获取值

I am working on a project where I have to use data from the dynamic JSON file. This is example of how JSON file could look.

我正在开发一个项目,我必须使用动态JSON文件中的数据。这是JSON文件的外观示例。

{
    "selectors": {
        "title": {
            "css": ".title"
        },
        "url": {
            "css": ".url"
        }
    }
}

Because the content of JSON file is dynamic, I can't access object like for example:

因为JSON文件的内容是动态的,所以我无法访问对象,例如:

var data = '{"selectors":{"title":{"css":".title"},"url":{"css":".url"}}}';
var json = JSON.parse(data);   
var element = json.selectors.title.css;

However, there are two objects that will always have same name, and those are selectors and css.

但是,有两个对象始终具有相同的名称,那些是selectors和css。

Now how can I access the objects title, url, category, time if they are dynamic? AND then to access css object trough those?

现在,如果它们是动态的,我如何访问对象标题,网址,类别和时间?然后通过那些访问css对象?

I need vanila JavaScript, not jQuery.

我需要vanila JavaScript,而不是jQuery。

1 个解决方案

#1

Because you don't know if a specific attribute exists you need to loop through all of them:

因为您不知道是否存在特定属性,所以您需要遍历所有属性:

var json = JSON.parse(data); 
for (key in json) {

}

but to make sure that you only loop through valid objects (and not something someone else might have tampered with) you should check for hasOwnProperty:

但是为了确保只循环通过有效对象(而不是其他人可能已经篡改过的东西),你应该检查hasOwnProperty:

var json = JSON.parse(data); 
for (key in json) {
  if (json.hasOwnProperty(key) {

  }
}

Now you are sure to loop through the first level of attributes, which in your example is only the attribute selectors. Now you can add another loop to check the 2nd level of attributes:

现在,您确定循环遍历第一级属性,在您的示例中,这些属性仅是属性选择器。现在您可以添加另一个循环来检查第二级属性:

var json = JSON.parse(data); 
for (key in json) {
  if (json.hasOwnProperty(key) {
    for (second_level in key) {
      if (key.hasOwnProperty(second_level) {
        if (second_level == 'title') { /* do something with title */ }
        if (second_level == 'url') { /* do something with url */ }
      }  
    }
  }
}

This can get a little messy, but because you expect a specific structure, you can just check for those attributes:

这可能会有点混乱,但因为您期望特定的结构,您可以检查这些属性:

if (json.hasOwnProperty('selectors') {
    if (json.selectors.hasOwnProperty('title') { /* do something with title*/ }
    if (json.selectors.hasOwnProperty('url') { /* do something with url */ }
}

We can access the attributes title and url directly because in your json these are objects ({}) and not arrays ([]), if they were arrays you would need to loop through them.

我们可以直接访问属性title和url,因为在你的json中这些是对象({})而不是数组([]),如果它们是数组,你需要循环它们。

Hope it helps

希望能帮助到你

#1