Understanding the undefined is not a function Error with Object.getOwnPropertyDescriptors in WebView

Описание: Discover why you encounter the `undefined is not a function` error when using `Object.getOwnPropertyDescriptors` in a WebView, along with debugging tips and alternative solutions.
---
This video is based on the question https://stackoverflow.com/q/65182557/ asked by the user 'Yaron' ( https://stackoverflow.com/u/6516970/ ) and on the answer https://stackoverflow.com/a/65182666/ provided by the user 'T.J. Crowder' ( https://stackoverflow.com/u/157247/ ) 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: Object.getOwnPropertyDescriptors(Node.prototype) fails

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.
---
Understanding the undefined is not a function Error with Object.getOwnPropertyDescriptors in WebView

When you're working on a web page running JavaScript, every developer expects certain methods to work flawlessly. However, if you've encountered an error stating undefined is not a function when using Object.getOwnPropertyDescriptors(Node.prototype) — especially in a WebView environment — you're not alone. This problem can be puzzling, particularly when your code works perfectly fine in a standard browser while exhibiting issues in WebView.

The Problem: Why Is It Happening?

Upon inspecting the situation, it's crucial to note that some implementations of JavaScript environments might not support certain functions. Specifically, in the case of the error you are experiencing, the likely culprits are:

JSON.stringify: This method was introduced in ECMAScript 5 (ES5).

Object.getOwnPropertyDescriptors: This method was added much later, in ECMAScript 2017.

It's very possible that the version of the JavaScript engine being used within the WebView does not include one or both of these functions, leading to the undefined is not a function error.

Testing and Debugging Your Environment

If you want to get to the bottom of this issue, follow these steps to perform further debugging.

Log User Agent String

Firstly, you should log the user agent string to gather information about the environment:

[[See Video to Reveal this Text or Code Snippet]]

This code will help you determine which part is unsupported in your JavaScript environment.

Alternative Solutions

Accessing Object Properties Safely

Following the error logs, you may find there is still a need to access object properties even when facing issues. For instance, if you're trying to get the childNodes property but it's showing undefined, you can create a function to traverse the prototype chain and find the property:

[[See Video to Reveal this Text or Code Snippet]]

Important Considerations

When dealing with host-provided objects like Node.prototype, it's essential to understand that they may not follow all JavaScript's typical rules. Therefore, approaching their properties may require additional caution and flexibility.

Conclusion

In summary, encountering the undefined is not a function error when using Object.getOwnPropertyDescriptors in WebView can be frustrating. By understanding the underlying reasons related to unsupported functions in your JavaScript environment and employing debugging strategies, you can uncover the root of the issue. Additionally, utilizing prototype chain traversal allows you to access properties more robustly when standard methods fail.

By informing yourself and applying these techniques, you'll be better equipped to handle JavaScript in various environments, ensuring a smoother development experience.