Web Scraping Js

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Web scraping at full power. With these tools we can log into sites, click, scroll, execute JavaScript and more. Cloud Functions + Scheduler Many scrapers are useless unless you deploy them.

  1. What is Web Scraping? Web scraping refers to the extraction of data from a website. This information is collected and then exported into a format that is more useful for the user. Be it a spreadsheet or an API.
  2. For node.js web scraping, we need to use certain packages, also known as libraries. These libraries are prepackaged code that can be reused. The packages can be downloaded and installed using the npm install command, which is the Node.js Package Manager. To install any package, simply run npm install.
  3. You can use web scraping to grab the data, with only a little extra work. Let’s see how we can use client-side web scraping with JavaScript. For an example, I will grab my user information from my public freeCodeCamp profile. But you can use these steps on any public HTML page.

We’d like to continue the sequence of our posts about Top 5 Popular Libraries for Web Scraping in 2020 with a new programming language - JavaScript.

JS is a quite well-known language with a great spread and community support. It can be used for both client and server web scraping scripting that makes it pretty suitable for writing your scrapers and crawlers.

Most of these libraries' advantages can be received by using our API and some of these libraries can be used in stack with it.

So let’s check them out.

The 5 Top JavaScript Web Scraping Libraries in 2020#

1. Axios#

Axios is a promise-based HTTP client for the browser and Node.js.But why exactly this library? There are a lot of libraries that can be used instead of a well-known request: got, superagent, node-fetch. But Axios is a suitable solution not only for Node.js but for client usage too.

Simplicity of usage is shown below:

axios.get('/user?ID=12345')
// handle success
})
// handle error
})
// always executed

Promises are cool, isn’t it?

To get this library you can use one of the preferable ways:

Using npm:

Using bower:

Using yarn:

GitHub repository: https://github.com/axios/axios

2. Cheerio#

Cheerio implements a subset of core jQuery. In simple words - you can just swap your jQuery and Cheerio environments for web scraping. And guess what? It has the same benefit that Axios has - you can use it from client and Node.js as well.

For the sample of usage, you can check another of our articles: Amazon Scraping. Relatively easy.

Also, check out the docs:

  • Official docs URL: https://cheerio.js.org/
  • GitHub repository: https://github.com/cheeriojs/cheerio

3. Selenium#

Selenium is a popular Web Driver that has a lot of wrappers for most programming languages. Quality Assurance engineers, automation specialists, developers, data scientists - all of them at least once have used this perfect tool. For Web Scraping it’s like a swiss knife - no additional libraries needed. Any action can be performed with a browser like a real user: page opening, button click, form filling, Captcha resolving and much more.

Selenium may be installed via npm with:

And the usage is a simple too:

const{Builder,By,Key, until}=require('selenium-webdriver');
(asyncfunctionexample(){
let driver =awaitnewBuilder().forBrowser('firefox').build();
await driver.get('http://www.google.com/');
await driver.sendKeys('webdriver',Key.RETURN);
await driver.wait(until.titleIs('webdriver - Google Search'),1000);
await driver.quit();
})();

More info can be found via the documentation:

  • Official docs URL: https://selenium-python.readthedocs.io/
  • GitHub repository: https://github.com/SeleniumHQ/selenium

4. Puppeteer#

There are a lot of things we can say about Puppeteer: it’s a reliable and production-ready library with great community support. Basically Puppeteer is a Node.js library that offers a simple and efficient API and enables you to control Google’s Chrome or Chromium browser. So you can run a particular site's JavaScript (as well as with Selenium) and scrape single-page applications based on Vue.js, React.js, Angular, etc.

We have a great example of using Puppeteer for scraping Angular-based website, you can check it here: AngularJS site scraping. Easy deal?

Also, we’d like to suggest you check out a great curated list of awesome Puppeteer resources: https://github.com/transitive-bullshit/awesome-puppeteer

As well, useful official resources:

  • Official docs URL: https://developers.google.com/web/tools/puppeteer
  • GitHub repository: https://github.com/GoogleChrome/puppeteer

5. Playwright#

Not as well-known a library as Puppeteer, but can be named as Puppeteer 2, since Playwright is a library maintained by former Puppeteer contributors. Unlike Puppeteer it supports Chrome, Chromium, Webkit and Firefox backend.

To install it just run the following command:

To be sure, that the API is pretty much the same, you can take a look at the example below:

for(const browserType of['chromium','firefox','webkit']){
const browser =await playwright[browserType].launch();
const page =await context.newPage();
await page.screenshot({ path:`example-${browserType}.png`});
}
  • Official docs URL: https://github.com/microsoft/playwright/blob/master/docs/README.md
  • GitHub repository: https://github.com/microsoft/playwright

Conclusion#

It’s always up to you to decide what to use for your particular web scraping case, but it’s also pretty obvious that the amount of data on the Internet increases exponentially and data mining becomes a crucial instrument for your business growth.

But remember, instead of choosing a fancy tool that may not be of much use, you should focus on finding out a tool that suits your requirements best.

Some websites can contain a very large amount of invaluable data.

Stock prices, product details, sports stats, company contacts, you name it.

If you wanted to access this information, you’d either have to use whatever format the website uses or copy-paste the information manually into a new document. Here’s where web scraping can help.

Web

What is Web Scraping?

Web scraping refers to the extraction of data from a website. This information is collected and then exported into a format that is more useful for the user. Be it a spreadsheet or an API.

Although web scraping can be done manually, in most cases, automated tools are preferred when scraping web data as they can be less costly and work at a faster rate.

But in most cases, web scraping is not a simple task. Websites come in many shapes and forms, as a result, web scrapers vary in functionality and features.

If you want to find the best web scraper for your project, make sure to read on.

How do Web Scrapers Work?

Automated web scrapers work in a rather simple but also complex way. After all, websites are built for humans to understand, not machines.

First, the web scraper will be given one or more URLs to load before scraping. The scraper then loads the entire HTML code for the page in question. More advanced scrapers will render the entire website, including CSS and Javascript elements.

Then the scraper will either extract all the data on the page or specific data selected by the user before the project is run.

Scraper

Ideally, the user will go through the process of selecting the specific data they want from the page. For example, you might want to scrape an Amazon product page for prices and models but are not necessarily interested in product reviews.

Lastly, the web scraper will output all the data that has been collected into a format that is more useful to the user.

Most web scrapers will output data to a CSV or Excel spreadsheet, while more advanced scrapers will support other formats such as JSON which can be used for an API.

Web Scraping Json Python

What Kind of Web Scrapers are There?

Web scrapers can drastically differ from each other on a case-by-case basis.

For simplicity’s sake, we will break down some of these aspects into 4 categories. Of course, there are more intricacies at play when comparing web scrapers.

  • self-built or pre-built
  • browser extension vs software
  • User interface
  • Cloud vs Local

Self-built or Pre-built

Just like how anyone can build a website, anyone can build their own web scraper.

However, the tools available to build your own web scraper still require some advanced programming knowledge. The scope of this knowledge also increases with the number of features you’d like your scraper to have.

On the other hand, there are numerous pre-built web scrapers that you can download and run right away. Some of these will also have advanced options added such as scrape scheduling, JSON and Google Sheets exports and more.

Browser extension vs Software

Web Scraping Json

In general terms, web scrapers come in two forms: browser extensions or computer software.

Browser extensions are app-like programs that can be added onto your browser such as Google Chrome or Firefox. Some popular browser extensions include themes, ad blockers, messaging extensions and more.

Web scraping extensions have the benefit of being simpler to run and being integrated right into your browser.

However, these extensions are usually limited by living in your browser. Meaning that any advanced features that would have to occur outside of the browser would be impossible to implement. For example, IP Rotations would not be possible in this kind of extension.

On the other hand, you will have actual web scraping software that can be downloaded and installed on your computer. While these are a bit less convenient than browser extensions, they make up for it in advanced features that are not limited by what your browser can and cannot do.

User Interface

The user interface between web scrapers can vary quite extremely.

For example, some web scraping tools will run with a minimal UI and a command line. Some users might find this unintuitive or confusing.

On the other hand, some web scrapers will have a full-fledged UI where the website is fully rendered for the user to just click on the data they want to scrape. These web scrapers are usually easier to work with for most people with limited technical knowledge.

Some scrapers will go as far as integrating help tips and suggestions through their UI to make sure the user understands each feature that the software offers.

Cloud vs Local

From where does your web scraper actually do its job?

Local web scrapers will run on your computer using its resources and internet connection. This means that if your web scraper has a high usage of CPU or RAM, your computer might become quite slow while your scrape runs. With long scraping tasks, this could put your computer out of commission for hours.

Additionally, if your scraper is set to run on a large number of URLs (such as product pages), it can have an impact on your ISP’s data caps.

Cloud-based web scrapers run on an off-site server which is usually provided by the company who developed the scraper itself. This means that your computer’s resources are freed up while your scraper runs and gathers data. You can then work on other tasks and be notified later once your scrape is ready to be exported.

Web Scraping Js

This also allows for very easy integration of advanced features such as IP rotation, which can prevent your scraper from getting blocked from major websites due to their scraping activity.

What are Web Scrapers Used For?

By this point, you can probably think of several different ways in which web scrapers can be used. We’ve put some of the most common ones below (plus a few unique ones).

  • Scraping site data before a website migration
  • Scraping financial data for market research and insights

The list of things you can do with web scraping is almost endless. After all, it is all about what you can do with the data you’ve collected and how valuable you can make it.

Read our Beginner's guide to web scraping to start learning how to scrape any website!

The Best Web Scraper

So, now that you know the basics of web scraping, you’re probably wondering what is the best web scraper for you?

The obvious answer is that it depends.

The more you know about your scraping needs, the better of an idea you will have about what’s the best web scraper for you. However, that did not stop us from writing our guide on what makes the Best Web Scraper.

Of course, we would always recommend ParseHub. Not only can it be downloaded for FREE but it comes with an incredibly powerful suite of features which we reviewed in this article. Including a friendly UI, cloud-based scrapping, awesome customer support and more.

Want to become an expert on Web Scraping for Free? Take ourfree web scraping courses and become Certified in Web Scraping today!