How to check if an Object is Empty in React

Check if an Object is Empty in React #

To check if an object is empty in React:

Use the Object.keys() method to get an array of the object's keys.
Access the length property on the array.
If the array of keys has a length of 0, then the object is empty.

App.js

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import {useEffect, useState} from 'react';

export default function App() {
  const [person, setPerson] = useState({});

  useEffect(() => {
    if (Object.keys(person).length === 0) {
      console.log('Object is empty');
    }

    if (Object.keys(person).length > 0) {
      console.log('Object is NOT empty');
    }
  }, [person]);

  return (
    <div>
      <h2>Object: {JSON.stringify(person)}</h2>

      <button onClick={() => setPerson({id: 1, name: 'Alice'})}>
        Set state
      </button>
    </div>
  );
}

react check if object is empty

We used the Object.keys method to get an array of all of the object's keys.

App.js

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const obj = {
  id: 1,
  name: 'Alice',
};

// 👇️ ['id', 'name']
console.log(Object.keys(obj));

const isEmpty = Object.keys(obj).length === 0;
console.log(isEmpty); // 👉️ false

The Object.keys method returns an empty array if the object has no key-value pairs (if it's empty).

App.js

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const obj = {};

// 👇️ []
console.log(Object.keys(obj));

const isEmpty = Object.keys(obj).length === 0;
console.log(isEmpty); // 👉️ true

An alternative approach is to try to iterate over the properties of the object. If there is even a single iteration, then the object is not empty.

App.js

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function isEmpty(obj) {
  for (const property in obj) {
    return false;
  }
  return true;
}

console.log(isEmpty({})); // 👉️ true
console.log(isEmpty({id: 1, name: 'Alice'})); // 👉️ false

If there is even 1 iteration, we know that the object has at least 1 key-value pair and is not an empty object.

If there aren't any iterations, then the object is empty.

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How to check if an Object is Empty in React

Check if an Object is Empty in React #

Borislav Hadzhiev