How To Build A Web Scraper With Javascript And Node.js

How to build a web scraper with Javascript and Node.Js
23 Oct

Web scraping lets you extract data from websites so that you can analyze the collected data to perform several tasks like:

  • Comparing the prices of your products with your competitors.
  • Collecting emails and contact details of prospects for sales outreach.
  • Checking the ratings and reviews of your brand.
  • Automating your social media marketing efforts by scraping the followers of your competitors and following them.
  • Conducting marketing analysis at scale to make better business decisions.

Every business, whether big or small, should use web scraping to achieve their business goals. 

JavaScript is a high-level programming language used to perform complex web scraping tasks along with Node.js that allows the execution of JavaScript code outside a web browser.  

In this article, we will learn how you can build a web scraper using JavaScript and Node.js but first, let’s understand how web scraping works and some other essentials related to web scraping. At the end of the article, we will discuss some of the best web scraping tools to make your scraping task much more manageable. 

Ready? Let’s begin!

What is web scraping?

Web scraping is also known by the names data scraping, data extraction, and web harvesting. It is a technique of automating extracting data from websites and storing it in a format for further analysis. 

The web scraping process works in two ways:

  • Fetching: The webpage is fetched using an HTML request library or a headless browser. Web crawling is a necessary component to download a page.
  • Extracting: Once the page is crawled, data extracting takes place. Extraction is the process of parsing and reformatting the data. The data is often stored in a spreadsheet or merged with a pre-existing master sheet that contains all the web scraping data. 

What is a proxy server?

A proxy server is used to mask your IP address so that the target websites can’t locate and ban your IP. A proxy acts as an intermediary between your computer and the target website. The target website sees the proxy server IP address as the primary IP addresses allowing you to browse the web anonymously. 

Why is a proxy server essential before you run your scraping program?

You should always use a proxy server for scraping because web scraping is an activity that can easily result in getting your IP blacklisted. Websites have mechanisms like anti-scraping tools and JavaScript checks to prevent scraping programs from accessing their website. When you try to use your scraping program to visit their website, they can easily detect the presence of a bot and blacklist your IP address. 

When you use a proxy, all the requests initiated by your scraping program goes through the proxy server. It is always recommended to choose residential proxies because they offer the highest level of anonymity. Moreover, the proxy offers you a collection of IP addresses and uses an IP rotation technique that changes the IP address associated with every browsing request. The anti-scraping tools allow browsing websites because the requests come from different locations and mimic regular user activity. 

Building a web scraper using JavaScript and Node.js

JavaScript is a modern programming language that adds interactive elements to a website. JavaScript is not a program that can interact directly with your computer. It interacts with your browser’s JavaScript engine and runs the code. 

However, when you use Node.js runtime environment with JavaScript, you enable it to run scripts on both the client-side and server-side.

Here are the steps for web scraping using JavaScript and Node.js:

Step 1: Identify the URL that you want to crawl. 

Step 2: Install the dependencies like Axios and Cheerios by using the below code:

$ mkdir scraper && cd scrapper

$ npm init -y

$ npm install –save axios cheerio

Step 3: Add them to your Index.js file. Here is the code you can use:

const siteUrl = “https://addurlyouwishtoscrape.com/”;

const axios = require(“axios”);

const fetchData = async () => {

const result = await axios.get(siteUrl);

return cheerio.load(result.data);

};

Step 4: Inspect the elements you want to target by clicking the Chrome developer tools’ Inspect option. Add the respective codes to your main file, depending on the elements that you wish to scrape.

Step 5: Store the data in a format of your choice. For example, to store the data in JSON file, use the following code:

const fs = require(‘fs’);

const getResults = require(‘../scraper’);

(async () => {

let results = await getResults()

let jsonString = JSON.stringify(results);

fs.writeFileSync(‘../output.json’, jsonString, ‘utf-8’);

})()

That’s it! These are the steps you need to follow to scrape any website using Json.js.

Building a web scraper using Javascript and Node.Js

Other ways to build a web scraper

There are several other ways to build a web scraper apart from JavaScript and Node.js. These methods are explained as follows: 

Combining the power of Python and Selenium 

You can use Python for web scraping. It is a high-level programming language that is best for scraping. Selenium is a Python library that helps to automate web browsers to do several tasks. All you need to do is to install the Selenium and then access the website using Python. You need to locate the element XPath to scrape the exact element. 

Using Puppeteer for web scraping 

Puppeteer is a node library to control headless Chrome. The Google Chrome development team manages it. You can use Puppeteer to automate form submissions or generate screenshots of pages. To start using Puppeteer, you first need to install it. You can combine Node.js with Puppeteer to scrape a website. Make sure to use a Proxy in Puppeteer

Top web scraping tools

If you are looking to build web scrapers with the least coding, then some tools can be used to handle browsers and captchas with a simple API call. 

Here are the top tools for web scraping:

Scrapy – It is an open-source framework to match all your web scraping needs. You only need to write your rules for data extraction, and Scrapy will do the rest. It is powered by Python and is exceptionally flexible. It runs on Linux, Mac, Windows, and BSD. Just import the Scrapy application framework in your program and start extracting the data you need. 

Beautiful Soup – It is another Python library that is extensively used for web scraping. Beautiful Soup is a powerful library for navigating, searching, and modifying a parse tree. You can do more with less coding. It has the ability to parse anything that you give it, making it a flexible library for all your data extraction needs. It has a vast discussion group where you can discuss any problems you might face when running custom scraping programs. You can use Beautiful Soup to select particular content on a webpage and store the copied data in a CSV file.

Octoparse – A free tool that lets you scrape websites within clicks. Octoparse works in three simple steps. You enter the URL to scrape, click on the element you want to copy, and start the data extraction process. The software will automatically scrape the exact data you selected and store it in CSV, Excel, API or any other database. You can even schedule tasks to automate your scraping at a specific time or day, and the software will complete the schedule run all by itself.

Mozenda – It is a trusted name in the world of web scraping tools. Mozenda uses a reliable web scraping technology that lets you harvest data 5x faster. You can scrape content from several formats like files, webpages, images, and PDFs. The data can be exported directly in different formats like CSV, XML, TSV, JSON, and others. If you are looking to perform data harvesting at scale, then Mozenda is the perfect solution for you.

Data Miner – Another useful software that claims to extract data from websites within minutes. One of the most significant advantages that you get by using this tool is that you get access to a collection of 50,000+ pre-made queries for a collection of 15,000+ websites. Hence, you don’t have to select individual elements and prepare separate coding to extract each of them. With pre-made queries, you can easily select the query that solves your data mining needs and extract the data within minutes.

DiffBot – This software lets you extract structured data from any website without codes. DiffBot offers seamless integration with your favorite apps like Google Sheets, Excel, Tableau, and Salesforce. The robust API offers 30+ different libraries to fulfill all your data harvesting needs. One of the best features of DiffBot is the DiffBot Knowledge Graph that leverages AI-enabled contextually linked data to copy data directly to your spreadsheet. 

Final Thoughts

Web scraping is essential for every business. There are different ways to scrape the web. You can use JavaScript to prepare data mining programs according to your business needs, or you can use the power of automatic tools to copy the data of your choice. No matter which method you choose for data harvesting, make sure to combine it with a proxy server’s power to hide your IP. Anonymous web scraping will give you faster results and keep your business reputation safe.

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