Counting the Number of Keys using for-in loop

Counting the Number of Keys using Object.keys

Counting the Number of Keys using Object.getOwnPropertyNames

We can also use for-in loop to iterate over the properties of an object and increment a counter for each property encountered. This approach allows us to count the number of keys without relying on any built-in methods.

Syntax:

let count = 0; for (let key in object) {    }

Example: Count the Number of keys using for-in loop. Here, we will count the number of keys in an object using a loop

Javascript

const user = {
    name: "Aman",
    age: 30,
    email: "Aman@example.com",
    address: {
        street: "Sector-15 A-Block",
        city: "Noida",
        state: "Up"
    }
};
 
let count = 0;
for (let key in user) {
    if (user.hasOwnProperty(key)) {
        count++;
    }
}
 
console.log("Number of keys: " + count);

Output

Number of keys: 4

Explanation:

The code initializes an object `user` with nested properties. It iterates through each key of `user` using a for…in loop, increments the count if the property is an own property, and logs the count to the console.

JavaScript Program to Count the Number of Keys/Properties in an Object

An object consists of key-value pairs where each key is a unique identifier associated with a corresponding value.

Several methods can be used to count the number of keys/properties in an object, which are listed below:

Table of Content

Counting the Number of Keys using Object.keys
Counting the Number of Keys using for-in loop
Counting the Number of Keys using Object.getOwnPropertyNames
Counting the Number of Keys using Object.entries
Counting the Number of Keys using JSON.stringify

Tags:

#JavaScript-DSA #JavaScript-Program #DSA #JavaScript #Web Technologies