How to Get a Key in a Javascript Object by Its Value?

How to get a key in a JavaScript object by its value?

Working with JavaScript objects is a common task for developers, and sometimes we may need to retrieve a key from an object based on its value. In this blog post, we will explore different solutions to accomplish this in JavaScript.

Solution 1: Using a for…in loop

One way to achieve this is by using a for…in loop to iterate over the object properties and check if the value matches the desired value. Here’s an example:

function getKeyByValue(object, value) {
  for (let key in object) {
    if (object[key] === value) {
      return key;
    }
  }
  
  return null; // Value not found
}

// Example usage
const myObject = {
  key1: 'value1',
  key2: 'value2',
  key3: 'value3'
};

const valueToFind = 'value2';
const key = getKeyByValue(myObject, valueToFind);
console.log(key); // Output: key2

Solution 2: Using Object.entries() and Array.find()

Another approach is to use the Object.entries() method to convert the object into an array of key-value pairs. Then, we can use the Array.find() method to search for the desired value and retrieve its corresponding key. Here’s an example:

function getKeyByValue(object, value) {
  const entries = Object.entries(object);
  const [key] = entries.find(([key, val]) => val === value) || [];
  
  return key || null; // Value not found
}

// Example usage
const myObject = {
  key1: 'value1',
  key2: 'value2',
  key3: 'value3'
};

const valueToFind = 'value3';
const key = getKeyByValue(myObject, valueToFind);
console.log(key); // Output: key3

These are two different approaches to retrieve a key from a JavaScript object based on its value. You can choose the one that best suits your needs and coding style.

Remember to handle cases where the value is not found in the object, as both solutions return null in those cases.

That’s it for this blog post! We hope you found these solutions helpful in your JavaScript development. If you have any questions or alternative approaches, feel free to share them in the comments below.