How to Iterate (Keys, Values) in Javascript?

How to Iterate (Keys, Values) in JavaScript?

When working with JavaScript, there may be times when you need to iterate over the keys and values of an object. This can be useful for various purposes, such as performing operations on each key-value pair or extracting specific information from the object. In this blog post, we will explore different methods to achieve this iteration.

Method 1: Using the for…in loop

The for...in loop is a built-in JavaScript loop that allows you to iterate over the enumerable properties of an object. By using this loop, you can easily access both the keys and values of an object.

Here’s an example:

const obj = { name: 'John', age: 30, city: 'New York' };

for (let key in obj) {
  console.log('Key:', key);
  console.log('Value:', obj[key]);
}

This code snippet will output:

Key: name
Value: John
Key: age
Value: 30
Key: city
Value: New York

Method 2: Using Object.entries()

The Object.entries() method returns an array of a given object’s own enumerable string-keyed property [key, value] pairs. This method provides a concise way to iterate over both the keys and values of an object.

Here’s an example:

const obj = { name: 'John', age: 30, city: 'New York' };

Object.entries(obj).forEach(([key, value]) => {
  console.log('Key:', key);
  console.log('Value:', value);
});

This code snippet will output the same result as the previous method:

Key: name
Value: John
Key: age
Value: 30
Key: city
Value: New York

Method 3: Using Object.keys()

The Object.keys() method returns an array of a given object’s own enumerable property names. Although this method only provides access to the keys of an object, you can easily retrieve the corresponding values using the keys.

Here’s an example:

const obj = { name: 'John', age: 30, city: 'New York' };

Object.keys(obj).forEach((key) => {
  console.log('Key:', key);
  console.log('Value:', obj[key]);
});

This code snippet will produce the same output as the previous methods:

Key: name
Value: John
Key: age
Value: 30
Key: city
Value: New York

These are three different methods you can use to iterate over the keys and values of an object in JavaScript. Depending on your specific use case, you can choose the method that best suits your needs.

Happy coding!

How to Iterate (Keys, Values) in Javascript?