how to check if a object in an array contains a key or not in React

Question

I am a novice to React and I am stuck in something. I have an array in the state which contains an object in it. The array looks like this:

myVar = [
      {
      "a": 1,
      "b":2
  },
  {
    "c":1,
    "d":1
  },
  {
    "e":"",
    "f":4
  }
  ];

I want to check somehow that does the array contains a key a or c or f by using this.state.myVar syntax. It doesn't matter what value it contains. It can be null.

I couldn't find a way to check it using JSX.

My output depends on it. Like if the array contains a key called a or c or f then it will display data depending on the available key. I can do this part but not sure how can I check for the availability of the key. Please Help me on that.

Possible duplicate stackoverflow.com/questions/237104/…

c-chavez
– c-chavez

2018-10-17 12:07:05 +00:00
Commented Oct 17, 2018 at 12:07 — c-chavez
– c-chavez, Commented Oct 17, 2018 at 12:07

Mayank Shukla · Accepted Answer · 2018-10-17 12:04:06Z

5

I couldn't find a way to check it using JSX.

This is not related to JSX or React. You need to iterate the array and check.

You can use any loop and hasOwnProperty to check whether the object has that key or not. One possible way to check is using #Array.some.

Like this:

myVar = [
  {
    "a": 1,
    "b":2
  },
  {
    "c":1,
    "d":1
  },
  {
    "e":"",
    "f":4
  }
];

let isKeyPresent = myVar.some(el => {
  if(el.hasOwnProperty('a') || el.hasOwnProperty('b') || el.hasOwnProperty('f'))
    return true;
})

console.log('isKeyPresent', isKeyPresent);

answered Oct 17, 2018 at 12:04

Mayank Shukla

105k19 gold badges163 silver badges146 bronze badges

Sign up to request clarification or add additional context in comments.

Comments

Ali BARIN · Accepted Answer · 2018-10-17 12:03:18Z

3

Actually it has nothing to do with React, JSX or another thing other than JavaScript itself. You can check if any of array items contains a key with the snippet below;

arr.some(item => item.hasOwnProperty('propertyName')) // returns boolean

So it will be something as below for your case;

myVar.some(item => item.hasOwnProperty('a'))

You can check this out to see how you can use the code in JSX.

answered Oct 17, 2018 at 12:03

Ali BARIN

1,92020 silver badges23 bronze badges

Comments

Chris Aby Antony · Accepted Answer · 2018-10-17 12:15:48Z

1

You can go through each array element by mapping it.

For example

myVar.map( function(item){ console.log(item) } )

Now you can check if the object item contains any of the required keys by using any one of the methods mentioned here. One method is as follows:

`myVar.map( function(item){ 
   if("a" in item){
    ...
   }
 })`

edited Oct 17, 2018 at 12:15

answered Oct 17, 2018 at 12:09

Chris Aby Antony

8114 silver badges9 bronze badges

Collectives™ on Stack Overflow

how to check if a object in an array contains a key or not in React

3 Answers 3

Comments

Comments

Comments

Your Answer

Linked

Hot Network Questions

Collectives™ on Stack Overflow

3 Answers 3

Comments

Comments

Comments

Your Answer

Sign up or log in

Post as a guest

Linked

Related