Node.js URL Module Practice Questions with Solutions

By /

Introduction

The Node.js URL module practice questions provides tools for creating, reading, and modifying URLs in Node.js applications. It is especially useful when working with web addresses, query parameters, paths, protocols, and search values. In this chapter, you will practice the modern WHATWG URL API with simple examples. These questions start with basic URL handling and gradually move toward practical tasks such as reading and updating query parameters.

Question 1: How do you create a URL object in Node.js?

Problem

Create a URL object for a website and display it.

Solution

const { URL } = require("url");

const website = new URL("https://example.com");

console.log(website);

Output

The console representation can vary slightly by Node.js version, but it represents:

URL {
  href: 'https://example.com/',
  ...
}

Step-by-Step Explanation

  1. Import the URL class from the built-in url module.
  2. Create a new URL object.
  3. Pass the complete URL as a string.
  4. Node.js parses the URL and stores its different parts.
  5. Display the URL object.

Important Point

Node.js provides the URL class globally in modern versions, but importing it from the url module is useful for clearly learning where the API comes from.

Question 2: How do you get the protocol from a URL?

Problem

Find the protocol of a website URL.

Solution

const { URL } = require("url");

const website = new URL(
    "https://example.com/about"
);

console.log(website.protocol);

Output

https:

Step-by-Step Explanation

  1. Create a URL object.
  2. Store the website URL.
  3. Access the protocol property.
  4. Node.js returns the protocol, including the colon.

For example:

https://example.com

has:

https:

as its protocol.

Question 3: How do you get the hostname from a URL?

Problem

Extract the hostname from this URL:

https://www.example.com/products

Solution

const { URL } = require("url");

const website = new URL(
    "https://www.example.com/products"
);

console.log(website.hostname);

Output

www.example.com

Step-by-Step Explanation

  1. Create a URL object.
  2. Pass the website URL.
  3. Access website.hostname.
  4. Node.js returns only the hostname.

The hostname is:

www.example.com

It does not include the protocol or path.

Question 4: How do you get the pathname from a URL?

Problem

Extract the path from this URL:

https://example.com/products/mobile/phones

Solution

const { URL } = require("url");

const website = new URL(
    "https://example.com/products/mobile/phones"
);

console.log(website.pathname);

Output

/products/mobile/phones

Step-by-Step Explanation

  1. Create a URL object.
  2. Pass the complete URL.
  3. Access the pathname property.
  4. Node.js returns the path portion.
  5. The result starts with /.

For:

https://example.com/products

the pathname is:

/products

Question 5: How do you get query parameters from a URL?

Problem

Read the name and age values from this URL:

https://example.com/profile?name=Riya&age=18

Solution

const { URL } = require("url");

const website = new URL(
    "https://example.com/profile?name=Riya&age=18"
);

const name = website.searchParams.get("name");
const age = website.searchParams.get("age");

console.log("Name:", name);
console.log("Age:", age);

Output

Name: Riya
Age: 18

Step-by-Step Explanation

  1. Create a URL object.
  2. The query string appears after ?.
  3. website.searchParams provides access to query parameters.
  4. Use .get("name") to retrieve the name.
  5. Use .get("age") to retrieve the age.
  6. Display both values.

The URL contains:

?name=Riya&age=18

Here:

  • name is a parameter.
  • Riya is its value.
  • age is a parameter.
  • 18 is its value.

Question 6: How do you add a query parameter to a URL?

Problem

Add course=Node.js to an existing URL.

Solution

const { URL } = require("url");

const website = new URL(
    "https://example.com/students"
);

website.searchParams.set(
    "course",
    "Node.js"
);

console.log(website.href);

Output

https://example.com/students?course=Node.js

Step-by-Step Explanation

  1. Create a URL object.
  2. Use searchParams.set().
  3. The first argument is the parameter name.
  4. The second argument is its value.
  5. Node.js adds the query parameter.
  6. Use href to get the complete updated URL.

Question 7: How do you update an existing query parameter?

Problem

Change the page value from 1 to 2.

Solution

const { URL } = require("url");

const website = new URL(
    "https://example.com/products?page=1"
);

website.searchParams.set("page", "2");

console.log(website.href);

Output

https://example.com/products?page=2

Step-by-Step Explanation

  1. Create the URL.
  2. The URL already contains a page parameter.
  3. Use searchParams.set().
  4. Specify the parameter name as "page".
  5. Provide the new value "2".
  6. Display the updated URL.

set() creates the parameter if it does not exist and replaces its value if it already exists.

Question 8: How do you delete a query parameter?

Problem

Remove the category parameter from this URL:

https://example.com/products?category=mobile&page=2

Solution

const { URL } = require("url");

const website = new URL(
    "https://example.com/products?category=mobile&page=2"
);

website.searchParams.delete("category");

console.log(website.href);

Output

https://example.com/products?page=2

Step-by-Step Explanation

  1. Create the URL object.
  2. Access searchParams.
  3. Use .delete().
  4. Provide the parameter you want to remove.
  5. category is removed.
  6. The page parameter remains.

Question 9: How do you check whether a query parameter exists?

Problem

Check whether the URL contains a username query parameter.

Solution

const { URL } = require("url");

const website = new URL(
    "https://example.com/login?username=Riya"
);

if (website.searchParams.has("username")) {
    console.log("Username parameter exists.");
} else {
    console.log("Username parameter does not exist.");
}

Output

Username parameter exists.

Step-by-Step Explanation

  1. Create the URL object.
  2. Access searchParams.
  3. Use .has("username").
  4. The method returns true when the parameter exists.
  5. The if statement displays the appropriate message.

For example:

website.searchParams.has("email");

would return false if the URL does not contain an email parameter.

Question 10: How do you build a URL dynamically using multiple query parameters?

Problem

Create a product search URL using:

  • Product = laptop
  • Category = electronics
  • Page = 2
  • Sort = price

Solution

const { URL } = require("url");

const website = new URL(
    "https://example.com/products"
);

website.searchParams.set(
    "product",
    "laptop"
);

website.searchParams.set(
    "category",
    "electronics"
);

website.searchParams.set(
    "page",
    "2"
);

website.searchParams.set(
    "sort",
    "price"
);

console.log(website.href);

Output

https://example.com/products?product=laptop&category=electronics&page=2&sort=price

Step-by-Step Explanation

  1. Create the base URL.
  2. Add the product parameter.
  3. Add the category parameter.
  4. Add the page parameter.
  5. Add the sort parameter.
  6. Use website.href to get the complete URL.
  7. Node.js automatically handles the query-string formatting.

This technique is useful when creating search URLs, filtering URLs, pagination links, and API request URLs.

Key Takeaways

  • Node.js provides a built-in url module.
  • The modern URL class makes URL handling easier.
  • You can import it using const { URL } = require("url").
  • url.protocol returns the URL protocol.
  • url.hostname returns the hostname.
  • url.pathname returns the path.
  • url.href returns the complete URL as a string.
  • url.searchParams provides access to query parameters.
  • searchParams.get() reads a parameter value.
  • searchParams.set() creates or updates a parameter.
  • searchParams.delete() removes a parameter.
  • searchParams.has() checks whether a parameter exists.
  • Query parameters are commonly used for searches, filters, pagination, and API requests.
  • The URL API automatically handles URL encoding when query parameters contain special characters.

FAQs

1. What is the URL module in Node.js?

The URL module is a built-in Node.js module that provides tools for parsing, creating, and modifying URLs.

A common way to use the modern URL API is:

const { URL } = require("url");

2. Do I need to install the URL module?

No. The url module is included with Node.js.

You can use:

const { URL } = require("url");

without installing an external package.

3. How do I get the hostname from a URL?

Create a URL object and access its hostname property:

const { URL } = require("url");

const website = new URL(
    "https://www.example.com/products"
);

console.log(website.hostname);

Output:

www.example.com

4. How do I get query parameters in Node.js?

Use searchParams.get():

const { URL } = require("url");

const website = new URL(
    "https://example.com/?name=Riya"
);

console.log(
    website.searchParams.get("name")
);

Output:

Riya

5. How do I add a query parameter to a URL?

Use searchParams.set():

website.searchParams.set(
    "page",
    "2"
);

For example:

https://example.com/products?page=2

6. How do I remove a query parameter from a URL?

Use searchParams.delete():

website.searchParams.delete(
    "page"
);

The specified parameter will be removed from the URL.

7. What is the difference between hostname and pathname?

hostname identifies the website host:

example.com

pathname identifies the path:

/products/mobile

For this URL:

https://example.com/products/mobile

the hostname is:

example.com

and the pathname is:

/products/mobile

Written by Shubhranshu Shekhar, who has trained 20000+ students in coding.

Related Posts

Scroll to Top