Home / Questions / 66164
Accepted
Dev 200
Asked: 2020-04-29 04:55:22 +0800 CST 2020-04-29 04:55:22 +0800 CST

JSON: get two different properties of two objects in one conversion with stringify

  • 772

Having the following JSON object:

var employees = {
      "staff": [{
        "firstName": "Tony",
        "lastName": "deAraujo",
        "age": 99
      }, {
        "firstName": "John",
        "lastName": "Smith",
        "age": 33
      }, {
        "firstName": "Mary",
        "lastName": "Adams",
        "age": 29
      }],
      "management": [{
        "firstName": "Judy",
        "lastName": "Garland",
        "age": 43
      }]
    };

I would like to know if it is possible to display in the same conversion with stringify:

firstNameand lastNameof staffand ageof management.

Since I know that it can be done separately like this:

 var resultado = JSON.stringify(employees, ["staff", "firstName","lastName"]);

 var resultado2 = JSON.stringify(employees, ["management", "age"]);

Try doing the following:

1) var resultado = JSON.stringify(employees, ["staff", "firstName","lastName" ,"management", "age"]);

But it returns firstName, lastName, ageboth from staffand from management.

{"staff":[{"firstName":"Tony","age":99},{"firstName":"John","age":33},{"firstName":"Mary","age":29},{"firstName":"Loren","age":29}],"management":[{"firstName":"Judy","age":43},{"firstName":"Loren","age":29}]}

two)var someString = JSON.stringify(employees, ["staff", "firstName","lastName"],["management", "age"]);

But it returns me alone firstNameandlastNamestaff

{"staff":[{"firstName":"Tony","lastName":"deAraujo"},{"firstName":"John","lastName":"Smith"},{"firstName":"Mary","lastName":"Adams"},{"firstName":"Loren","lastName":"Santos"}]}

Expected result:

{"staff":[{"firstName":"Tony","lastName":"resultado"},{"firstName":"John","lastName":"resultado"},{"firstName":"Mary","lastName":"resultado"},{"firstName":"Loren","lastName":"resultado"}],"management":[{"age":"43","age":"23"}}

I guess something like this, I think I'm missing commas and braces.

json

1 Answers

  1. Best Answer

    I think using JSON.stringifyto do this process this way is overcomplicating. Going through the array you can choose the keys that will be part of your new JSON. (First example)

    Although if you want you can use the second argument of JSON.stringifybut instead of passing it an Array, you must pass it a function. In this function (which receives the clavey valorof the object it is converting to string) we check the key and format the content of staffy managementso that the objects inside those Arrays contain only the properties we want (Second example)

    var employees = {"staff":[{"firstName":"Tony","lastName":"deAraujo","age":99},{"firstName":"John","lastName":"Smith","age":33},{"firstName":"Mary","lastName":"Adams","age":29}],"management":[{"firstName":"Judy","lastName":"Garland","age":43}]};

let fnParse = (key, array) => 
  key == 'staff' 
    ? array[key].map( ({firstName, lastName}) => ({firstName, lastName}) )
    : array[key].map( ({age}) => ({age}) )

let formatted = 
  Object
  .keys(employees)
  .reduce( (obj, key) => (obj[key] = fnParse(key, employees), obj), {})

console.log(JSON.stringify(formatted));

let formattedStr = JSON.stringify(employees, (key, val)=>{
  if(key == 'staff') 
    return val.map( ({firstName, lastName}) => ({firstName, lastName}) );
  if(key == 'management') 
    return val.map( ({age}) => ({age}) );
  return val;
});
console.log(formattedStr);

    To see the code in ES5 Click here

    • 3