Get typeof element inside of JSON object

Question

I have a JSON file and with the help of @Supercool was able to get key names for each. I wanted to be able to get the type of values.

JSON Structure:

[
    {
        "id": 1536700,
        "title": "final_output",
        "error": "",
        "data": [
            {
                "metric": 4940616.0,
                "title": "d_revenue"
            },
            {
                "metric": 5132162.0,
                "title": "p_revenue"
            },
            {
                "metric": 4954576.0,
                "title": "s_revenue"
            },
            {
                "metric": 4882217.0,
                "title": "u_revenue"
            },
            {
                "metric": 4869609.0,
                "title": "t_revenue"
            },
            {
                "metric": 5075422.0,
                "title": "w_revenue"
            },
            {
                "metric": 4461996.0,
                "title": "v_revenue"
            }
        ]
    }
]

Next Structure:

[
    {
        "run_id": 1536700,
        "code_title": "select_data",
        "error": "",
        "data": [
            {
                "user_name": "C_51",
                "num1": 51,
                "num2": 101,
                "num3": 151
            },
            {
                "user_name": "H_51",
                "num1": 51,
                "num2": 101,
                "num3": 151
            },
            {
                "user_name": "C_52",
                "num1": 52,
                "num2": 102,
                "num3": 152
            },
            {
                "user_name": "H_52",
                "num1": 52,
                "num2": 102,
                "num3": 152
            },
            {
                "user_name": "C_53",
                "num1": 53,
                "num2": 103,
                "num3": 153
            }
        ]
    }
]

Use Object.keys(yourObject) to get the keys

 $.getJSON(api, function(elem) {
      let keys=elem.map( structure =>  Object.keys(structure.data[0]))         
   });

Run the following snippet to check if it works

 let ele= [{"id": 1536700,"title": "final_output","error": "",
"data": [{"metric": 4940616.0,"title": "d_revenue"},{"metric": 5132162.0,"title": "p_revenue"},{"metric":4954576.0,"title": "s_revenue"},{"metric": 4882217.0,"title":"u_revenue"},{"metric": 4869609.0,"title":"t_revenue"},{"metric": 5075422.0,"title": "w_revenue"},{"metric": 4461996.0,"title": "v_revenue"}
]
},
{"run_id": 1536700,"code_title": "select_data","error": "",
  "data": [{"user_name": "C_51","num1": 51,"num2": 101,"num3": 151},{"user_name": "H_51","num1": 51,"num2": 101, "num3": 151},{"user_name": "C_52","num1": 52,"num2": 102,"num3": 152},{"user_name": "H_52","num1": 52,"num2": 102,"num3":152},{"user_name": "C_53","num1": 53,"num2": 103,"num3": 153}
]}]
 console.log(ele.map( structure =>  Object.keys(structure.data[0])))
 console.log(ele.map( structure =>  Object.values(structure.data[0])))

.as-console-wrapper { max-height: 100% !important; top: 0; }

I want to be able to get the type of each of the values. Is it possible for me to get this for the values listed above?

[
  [
    number,
    string
  ],
  [
    string,
    number,
    number,
    number
  ]
]

Instead of keeping that in an array, you could convert it to an object with values replaced to types. Not sure what you need it for though, but I'm almost 100% positive you do something funny. — Robo Robok, Apr 06 '20 at 16:32
`ele.map(structure => Object.values(structure.data[0]).map(v => typeof v))` — Đinh Carabus, Apr 06 '20 at 16:33

score 1 · Accepted Answer · answered Apr 06 '20 at 16:35

1

let ele = [{"id": 1536700,"title": "final_output","error": "", "data": [{"metric": 4940616.0,"title": "d_revenue"},{"metric": 5132162.0,"title": "p_revenue"},{"metric":4954576.0,"title": "s_revenue"},{"metric": 4882217.0,"title":"u_revenue"},{"metric": 4869609.0,"title":"t_revenue"},{"metric": 5075422.0,"title": "w_revenue"},{"metric": 4461996.0,"title": "v_revenue"}]}, {"run_id": 1536700,"code_title": "select_data","error": "", "data": [{"user_name": "C_51","num1": 51,"num2": 101,"num3": 151},{"user_name": "H_51","num1": 51,"num2": 101, "num3": 151},{"user_name": "C_52","num1": 52,"num2": 102,"num3": 152},{"user_name": "H_52","num1": 52,"num2": 102,"num3":152},{"user_name": "C_53","num1": 53,"num2": 103,"num3": 153}]}];

console.log(ele.map(structure => Object.values(structure.data[0]).map(v => typeof v)));

answered Apr 06 '20 at 16:35

Đinh Carabus

2,443
3
17
34

Just keep in mind that JavaScript does not guarantee object property order in every case. – Đinh Carabus Apr 06 '20 at 16:42
using map will guarentee it https://stackoverflow.com/questions/5525795/does-javascript-guarantee-object-property-order – M A Salman Apr 06 '20 at 16:46
@Supercool. `map` doesn't guarantee property order, its the call to `Object.values()` which does. – r3wt Apr 06 '20 at 17:12

score 1 · Answer 2 · answered Apr 06 '20 at 16:37

Do a map() through Object.values(obj) and use typeof value to return the type

let ele= [{"id": 1536700,"title": "final_output","error": "",
"data": [{"metric": 4940616.0,"title": "d_revenue"},{"metric": 5132162.0,"title": "p_revenue"},{"metric":4954576.0,"title": "s_revenue"},{"metric": 4882217.0,"title":"u_revenue"},{"metric": 4869609.0,"title":"t_revenue"},{"metric": 5075422.0,"title": "w_revenue"},{"metric": 4461996.0,"title": "v_revenue"}
]
},
{"run_id": 1536700,"code_title": "select_data","error": "",
  "data": [{"user_name": "C_51","num1": 51,"num2": 101,"num3": 151},{"user_name": "H_51","num1": 51,"num2": 101, "num3": 151},{"user_name": "C_52","num1": 52,"num2": 102,"num3": 152},{"user_name": "H_52","num1": 52,"num2": 102,"num3":152},{"user_name": "C_53","num1": 53,"num2": 103,"num3": 153}
]}]
console.log("Keys are ..");
 console.log(ele.map( structure =>  Object.keys(structure.data[0])))
console.log("and their correspondent value types are ..."); 
 console.log(ele.map( structure =>  Object.values(structure.data[0]).map(value => typeof value)))

.as-console-wrapper { max-height: 100% !important; top: 0; }

score 0 · Answer 3 · edited Apr 06 '20 at 16:38

0

Javascript is a prototype language, so you can use the constructor.name property on any structure in js to see what type it is.

simple example:

const a = { t: 5, s: '', d: false, e:[], f:{}, d:5.53 };
for (let k in a) {
  console.log(k,a[k].constructor.name);
}

edited Apr 06 '20 at 16:38

mplungjan

134,906
25
152
209

answered Apr 06 '20 at 16:37

r3wt

4,262
2
28
52

1

Made a snippet and added the key since it does not log in order – mplungjan Apr 06 '20 at 16:39
map will guarantee it https://stackoverflow.com/questions/5525795/does-javascript-guarantee-object-property-order – M A Salman Apr 06 '20 at 16:46

Get typeof element inside of JSON object

3 Answers3