How to Simplify Your Web Scraping Code and Avoid Type Errors скачать в хорошем качестве

How to Simplify Your Web Scraping Code and Avoid Type Errors

Learn how to streamline your web scraping code using Puppeteer to avoid type errors and enhance efficiency. --- This video is based on the question https://stackoverflow.com/q/72195195/ asked by the user 'Wave' ( https://stackoverflow.com/u/18537095/ ) and on the answer https://stackoverflow.com/a/72195286/ provided by the user 'CertainPerformance' ( https://stackoverflow.com/u/9515207/ ) at 'Stack Overflow' website. Thanks to these great users and Stackexchange community for their contributions. Visit these links for original content and any more details, such as alternate solutions, latest updates/developments on topic, comments, revision history etc. For example, the original title of the Question was: Can I simplify this code to avoid the type error for reading properties? Also, Content (except music) licensed under CC BY-SA https://meta.stackexchange.com/help/l... The original Question post is licensed under the 'CC BY-SA 4.0' ( https://creativecommons.org/licenses/... ) license, and the original Answer post is licensed under the 'CC BY-SA 4.0' ( https://creativecommons.org/licenses/... ) license. If anything seems off to you, please feel free to write me at vlogize [AT] gmail [DOT] com. --- How to Simplify Your Web Scraping Code and Avoid Type Errors Web scraping can be a powerful tool for gathering data from various websites, but it often comes with its own set of challenges. One common issue developers face is encountering type errors, especially when trying to access properties of undefined elements. If you're using Puppeteer for web scraping and have run into problems like TypeError: Cannot read properties of undefined, you're in the right place. In this guide, we’ll explore a common scenario where developers encounter this issue and provide a solution to simplify your code and improve its reliability. The Problem: Type Errors in Web Scraping When scraping information from a webpage, developers often rely on elements being present at specific XPath locations. However, as your code runs, certain elements may not always exist, leading to errors when attempting to access them. For instance, you might see an error like: [[See Video to Reveal this Text or Code Snippet]] This usually occurs if the selector does not find an element at the specified XPath, resulting in el being undefined. Let’s take a look at a sample piece of code that could trigger this type of error: [[See Video to Reveal this Text or Code Snippet]] The Solution: Checking for Element Existence The first step to resolving this issue is to ensure that you check for the existence of an element before trying to call methods on it. You can use a simple conditional check to provide a fallback value if an element isn’t found. Here’s how you can modify the above code: [[See Video to Reveal this Text or Code Snippet]] This adjustment ensures that if the element doesn’t exist, you’ll receive a ‘Not Found’ string instead of encountering an error. Streamlining Your Code Structure To reduce repetition in your code and enhance maintainability, consider creating an array of elements to find, along with their corresponding property names. Then, loop through this array to retrieve your data. Here’s an example approach: Step 1: Define Elements and Properties Create an array that includes the XPath of each element and its corresponding name: [[See Video to Reveal this Text or Code Snippet]] Step 2: Gather Results Next, use a loop to find each element and store the results in an object: [[See Video to Reveal this Text or Code Snippet]] Step 3: Utilize the Results Now that you have gathered all the information in a single object, you can easily access your results and use them as needed: [[See Video to Reveal this Text or Code Snippet]] Conclusion By incorporating these checks and organizing your scraping logic, you can significantly reduce the chances of running into type errors. Not only does this make your code cleaner, but it also enhances its robustness, ensuring that even if some elements are missing from the page, your script continues to function smoothly. Feel free to adapt this method to include more elements or adjust the fallback values based on your needs! Happy scraping!