访问嵌套对象-Javascript

Question

我有一个设置验证规则，该规则将应用于一组对象。我需要更深入地研究“ contentType”并编写验证。

{
"_id" : ObjectId("5b3570f3150a0b57a4e7421e"),
"children" : [ 
    {
        "fullName" : "John doe",
        "yearGroup" : "4",
        "absences" : [],
        "id" : "765"
    }
],
"email" : "jdoe@gmail.com",
"firstName" : "John",
"lastName" : "Doe",
"role" : "parent",
"__v" : 1

下面的验证可以访问“ obj键”和“规则键”。

我无法更深入地了解我们在哪里可以访问rule [key]的键和obj [key]的键。

var rules=  {
         p1: {
             required:true,
             pgName:"string", 
             maxLength:5,
             contentType: {main:"string", Id: "string"}

             },
         p2: {
           required:true,
           pgName:"string",
           maxLength:5
             },
         p3: {
           required: true, 
           pgName:"string", 
           maxLength:5,
           contentType: {sub:"string", Id: "string"}

           }
        }

    obj= {
          p1: {
            pgName:"page1",
            contentType: {main:"template obj", Id: "af3323443"}
            },
          p2: {
            pgName:"page2", 
            },
          p3: {pgName:"page3",
              contentType: {main:"template obj2", Id: "af35455"}}
        };

  

我需要包括“ contentType”属性，以使用上面的代码进行验证。