In this article we will learn how to extract values from query strings and path parameters from an Express.js request. In Express.js routes / services we needs to get values from query strings and route params and use them in the business logic. This tutorial explains the process of extracting these values after validations.

Extract Query Parameters

Let’s take an example URL.

http://app-example.poopcode.com:8010/api/dashboard?type=user&format=bar

The above API fetches dashboard for type user and format bar.

To fetch these values you can use req.query.type and req.query.format

let type = req.query.type;
let format = req.query.format;
console.log(type); //user
console.log(format); //bar

Extract Path Parameters

The same URL that we used in the previous example can also be framed to use path params.

http://app-example.poopcode.com:8010/api/dashboard/user/bar

Your route configuration would look something like this.

routes.get('/:type/:format', dashboardService.getHomePage(req, res);
})

Here type user and format bar are passed in the URL as path parameters.

To extract these values in the code, you can use req.params.type and req.params.format

let type = req.params.type;
let format = req.params.format;
console.log(type); //user
console.log(format); //bar