Javascript: Find in json array and push to array object if no key found

Question

I have a json array as:

  0: {Id: "1", name: "Adam", Address: "123", userId: "i98"}
  1: {Id: "2", name: "John", Address: "456"}

Now in the above array, the second one has no userId key available.

How can I loop through the above array and check if no userId key available then add the key with value 0. For eg add userId: "0"

What I have tried is the following:

let jsonData = JSON.parse(JSON.stringify(userData));

 for (const obj of jsonData) {
    var hasId = false;
      let objId = obj.find((o, i) => {
         if (o.userId === "userId") {
          hasId = true;
        }
      });
      if (!hasId) {
         obj.push();
       }
    }

But this gives me error:

obj.find is not a function

Any inputs to resolve my issue and push the key value to the array.

"I have a json array" - No, that's an array of objects. JSON is a textual, language-indepedent data-exchange format, much like XML, CSV or YAML. — Andreas
– Andreas, Commented Jul 27, 2018 at 16:04

Eddie · Accepted Answer · 2018-07-27 16:24:10Z

3

On your code, obj is an object and there is no find method on objects. If you want to check if an object has an array you can just if( obj.userId )

You can use forEach to loop thru the array.

let jsonData  = [{Id: "1", name: "Adam", Address: "123", userId: "i98"},{Id: "2", name: "John", Address: "456"}];

jsonData.forEach(o => {
  o.userId = o.userId || 0; //Assign 0 if userId is undefined.
})

console.log(jsonData);

edited Jul 27, 2018 at 16:24

answered Jul 27, 2018 at 16:06

Eddie

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2 Comments

Eddie Over a year ago

Happy to help :)

aman Over a year ago

it's not related but could you look at one of my other question stackoverflow.com/questions/51485838/… I am not getting any helpful replies on this. Thanks

Mamun · Accepted Answer · 2018-07-27 16:17:37Z

2

You can make use of Array.prototype.map() and Object.prototype.hasOwnProperty() like the following way:

var jsonData = [{Id: "1", name: "Adam", Address: "123", userId: "i98"},{Id: "2", name: "John", Address: "456"}]

jsonData = jsonData.map(i => {
  if(!i.hasOwnProperty('userId'))
    i.userId = 0;
  return i;
});

console.log(jsonData);

edited Jul 27, 2018 at 16:17

answered Jul 27, 2018 at 16:07

Mamun

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