JavaScript is all about objects, keys, arrays, values, variables, etc. All these are used to make the program that works to enhance the interactivity of websites. Programmers have been using JavaScript to design interactive programs. Beginners often land in programming issues and look for a way out. Get an Object’s Key by its Value using JavaScript is among the programs that you would like to get through smoothly.

Today we discuss the ways to get an object’s keys by its value. An object consists of values and keys that can also be known as properties. Let’s shed light on how to code well to get an object’s keys by its value using JavaScript

How to get an object’s keys by its value Using JavaScript?

There are methods to get an object’s keys by its value. Take a look at the methods

• The Object.keys() method
• The find() method
• The Array find() method
• The Array filter() method

Using the Object.keys() Method with the find()

This method is used to get an array of keys of an object. The purpose of the Object.keys() method is that it returns an array of every key by taking an object. With the help of Object.Keys() you can get the object’s keys, and then the find() method is used to find the key that is associated with the specified value.

function getObjectKey(obj, value) {
  return Object.keys(obj).find((key) => obj[key] === value);
}

const obj = {
  user1: 'John',
  user2: 'Kate',
  user3: 'Peter',
};
const key = getObjectKey(obj, 'Kate');
console.log(key); // user2

To get an array of all the keys of the object

const obj = {
  user1: 'John',
  user2: 'Kate',
  user3: 'Peter',
};

const keys = Object.keys(obj);
console.log(keys); // [ 'user1', 'user2', 'user3' ]

You can get a ‘True’ in return when using ‘find()’ method if the equality check works and succeed. And it doesn’t return ‘True’, you get an ‘undefined’ in return.

const obj = {
  user1: 'John',
  user2: 'Kate',
  user3: 'Peter',
};
const keys = Object.keys(obj);
console.log(keys); // [ 'user1', 'user2', 'user3' ]

Using the Array find() method

If the object used contains multiple keys and all of them with the same value, you will only get the first key in the return

function getObjectKey(obj, value) {
  return Object.keys(obj).find((key) => obj[key] === value);
}

const obj = {
  user1: 'John',
  user2: 'Kate',
  user3: 'Peter',
  user4: 'John',
};

const key = getObjectKey(obj, 'John');
console.log(key); // user1

Using the Array filter() method

If the keys have different values, then you need to use the Array filter() method instead of find().

function getObjectKey(obj, value) {
  return Object.keys(obj).filter(
    (key) => obj[key] === value
  );
}

const obj = {
  user1: 'John',
  user2: 'Kate',
  user3: 'Peter',
  user4: 'John',
};

const key = getObjectKey(obj, 'John');
console.log(key); // ['user1', 'user4']

with the filter() method, you will get an array of the keys in return with matching values.

Conclusion

With the multiple ways to get an object’s key by its value using JavaScript, I hope you can crack the code easily.

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