Summary - URL and query string

Combine URL, URLSearchParams and querystring to write a URL parser.

Summary - URL and query string

In this group you learned Node.js's URL tools: parsing with new URL(), query management with URLSearchParams, properties like pathname/hostname, relative resolution with new URL(relative, base), and the querystring module. Now we will combine them in a URL parser.

Structure: parse a URL with new URL(), turn its query into an object with querystring.parse, print hostname and query values on separate lines. This is the foundational step of a real web scraper or API client: you first parse the address, then take the query parameters. The output is deterministic because the address and query are fixed.

Exercise Write a URL parser

Create a URL with const url = new URL("https://example.com:8080/path?q=merhaba&s=1");. Import with const querystring = require("node:querystring");. Parse the query with const parsed = querystring.parse(url.search.slice(1)); (skip the ? with slice(1)). Print with console.log(url.hostname), console.log(parsed.q) and console.log(parsed.s).

Show example solution

const url = new URL("https://example.com:8080/path?q=merhaba&s=1");
const querystring = require("node:querystring");
const parsed = querystring.parse(url.search.slice(1));
console.log(url.hostname);
console.log(parsed.q);
console.log(parsed.s);

Test yourself

What is the modern way to get a URL's query parameters?
```
url.searchParams.get("q")
```
- Only regex
- Only String.split("&")
- URLSearchParams veya url.searchParams
- Only the querystring module
Show answer

URLSearchParams veya url.searchParams — URLSearchParams is the modern and recommended way.
Match each tool to its purpose

new URL()

Parses address
URLSearchParams

Manages query
pathname

Path component
querystring

Legacy query module

Complete the URL construction

const url = new ____(adres);

Show answer

const url = new URL(adres);

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