Скачать или смотреть How to Access Class Private Properties Inside Nested Functions in JavaScript

Discover how to effectively access class private properties in JavaScript nested functions, allowing seamless method invocation within your constructor.
---
This video is based on the question https://stackoverflow.com/q/72088736/ asked by the user 'L. Ouellet' ( https://stackoverflow.com/u/12458881/ ) and on the answer https://stackoverflow.com/a/72088852/ provided by the user 'Apollo79' ( https://stackoverflow.com/u/17797907/ ) 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: access class private property inside nested method and function?

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.
---
Navigating JavaScript Class Private Properties in Nested Functions

JavaScript is a powerful language that allows for advanced programming techniques, including the use of classes and private properties. However, it can become tricky when you try to access private properties within nested functions. In this guide, we will tackle a specific case where developers encounter the error Uncaught TypeError: this.status is not a function and provide a precise solution.

The Challenge

When working with the Logger class, you may wish to call a method named status inside a nested function, such as within the constructor where console methods are being overridden. The error occurs because this does not point to the Logger instance within the nested function context but rather to the function's own execution context.

Here's the crucial part of the code that presents the issue:

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

In the above snippet, when this is used, it is not referring to the Logger instance but to the object that the function is being invoked upon. Thus, we encounter the error.

The Solution

To resolve this issue, we can create a reference to the this context of the Logger class. By doing this, we maintain access to all properties and methods of the Logger instance. Here's how you can do it:

Step 1: Create a Self Reference

At the beginning of the constructor, assign this to a new variable called self. This allows us to access the Logger instance from within the nested functions.

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

Step 2: Use the Self Reference in Nested Functions

Now, inside your nested functions—where you were originally attempting to use this—replace it with self. This guarantees that you are referring to the Logger instance.

Here’s the modified version of the Logger class:

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

Conclusion

By employing a self-reference, you can efficiently access your class's private properties inside nested functions. This method helps you overcome the common pitfalls associated with the this keyword in JavaScript, ensuring that your code functions properly across various scopes.

Next time you encounter a similar scenario, remember to create a self-reference and enjoy seamless access to your private methods and properties!

Happy coding!