从JSON创建对象数组

Question

I have a JSON file like below:

[

{"fields":{category_class":"CAT2",category_name":"A"},"pk":1 },

{"fields":{category_class":"CAT1",category_name":"B"},"pk":2 },

{"fields":{category_class":"CAT1",category_name":"C"},"pk":3 },

{"fields":{category_class":"CAT2",category_name":"D"},"pk":4 },

{"fields":{category_class":"CAT3",category_name":"E"},"pk":5 },

{"fields":{category_class":"CAT1",category_name":"E"},"pk":6 },

]

I want to create an array of objects from the above JSON which will have two properties. i) CategoryClass ii) CategoryNameList. For example:

this.CategoryClass = "CAT1"
this.CategoryNameList = ['B','C','E']

Basically i want to select all categories name whose category class is CAT1 and so forth for other categories class. I tried this:

var category = function(categoryClass, categoryNameList){

this.categoryClass = categoryClass;
this.categoryList = categoryNameList;

}

var categories = [];

categories.push(new category('CAT1',['B','C','E'])

Need help.

Answer 1

You can use a simple filter on the array. You have a few double quotes that will cause an error in you code. But to filter only with CAT1 you can use the filter method

var cat1 = arr.filter( value => value.fields.category_class === "CAT1");

Answer 2

Question : Basically i want to select all categories name whose category class is CAT1 and so forth for other categories class

Solution :

function Select_CatName(catclass,array){
  var CatNameList=[]
  $(array).each(function(){
  if(this.fields.category_class==catclass)
    CatNameList.push(this.fields.category_name)
 })
return CatNameList;
}

This function return the Desired Category Name List, you need to pass desired catclass and array of the data , as in this case it's your JSON.

Input :

Above function calling :

Output :

Hope It helps.

Answer 3

I would suggest this ES6 function, which creates an object keyed by category classes, providing the object with category names for each:

 function groupByClass(data) { return data.reduce( (acc, { fields } ) => { (acc[fields.category_class] = acc[fields.category_class] || { categoryClass: fields.category_class, categoryNameList: [] }).categoryNameList.push(fields.category_name); return acc; }, {} ); } // Sample data var data = [ {"fields":{"category_class":"CAT2","category_name":"A"},"pk":1 }, {"fields":{"category_class":"CAT1","category_name":"B"},"pk":2 }, {"fields":{"category_class":"CAT1","category_name":"C"},"pk":3 }, {"fields":{"category_class":"CAT2","category_name":"D"},"pk":4 }, {"fields":{"category_class":"CAT3","category_name":"E"},"pk":5 }, {"fields":{"category_class":"CAT1","category_name":"E"},"pk":6 }, ]; // Convert var result = groupByClass(data); // Outut console.log(result); // Example look-up: console.log(result['CAT1']);