URL Parameters vs Query String in Express.js

What URL parameters are .

So before looking at URL parameters, we should first understand what the problem statement is. After that, we will be able to understand what it actually is.

• So the problem statement is this, assume there is a resource available on the internet. How will you access that particular resource? Take the example of a website. There are many websites available on the internet with different names and different purposes. So how will we access them? This problem is solved by the URL.

• URL means Uniform Resource Locator. It is a unique address for every website with the help of which we can access any resource on the internet. It is kind of a particular location. Now, inside URL parameters there can be condition-based resources. For example, on a specific path we may get something specific, or there can be query parameters where the user searches something and then gets some data. We will discuss this in the next section.

What query parameters are .

Query parameters mean accessing a resource by entering some query, if that resource is available on the internet. These parameters usually come in the form of key-value pairs. With the help of the key, we can access specific data or resources.

• Query parameters always start after the end of the URL path, and they begin with a ? symbol. After that, the key and value are written in the format of key=value.

For example:

https://nikhil.com/search?query=javascript

• In this example, query is the key and javascript is the value. Based on this query, the server can return related data or resources.

• Multiple query parameters can also be passed in a single URL, and they are separated using the & symbol.

https://example.com/products?category=mobile&brand=apple

Difference between them .

The main difference is that a URL is the complete address of a resource, while query parameters are extra values ​​added inside the URL to get specific data or perform some condition-based operation.

A URL helps us locate and access a resource on the internet. It contains things like the protocol, domain name, and path of the resource.

URL can work without query parameters, but query parameters cannot work without a URL because they are always part of the URL.

Accessing params in Express .

Accessing params in Express means getting values ​​from the URL . In Express, parameters are mainly accessed in two ways.

1. Route Params

2. Query Params

• Route params are used when we want to access a specific resource based on its unique value inside the URL path.

• app.get("/user/:name", (req, res) => { 
  console.log(req.params.name);
  })
  
  // req.params :- used for values ​​coming from the URL path.
  

Accessing query strings in Express .

import express from "express";

const app = express();

app.get("/user", (req, res) => {
  const name = req.query.name;
  const course = req.query.course;

  res.send(`Category: \({name}, Brand: \){course}`);
});

app.listen(3000, () => {
  console.log("Server running on port 3000");
});

When to use params vs query .

Params and query are both used to send data through the URL, but they are used in different situations.

• Route params are used when we want to access a specific resource using a unique value inside the URL path. They are mostly used for required values ​​.

• On the other hand, query parameters are used when we want filtered, optional, or condition-based data from a resource. They are mostly used for searching, filtering, sorting, pagination, and similar operations.