Скачать или смотреть Resolving the is not a known element Error in Your Angular 9 Custom Library

A comprehensive guide to troubleshooting the `is not a known element` error in Angular 9 custom libraries, including detailed steps to create a custom library and resolve common issues.
---
This video is based on the question https://stackoverflow.com/q/62315080/ asked by the user 'A. Pine' ( https://stackoverflow.com/u/5583602/ ) and on the answer https://stackoverflow.com/a/62722822/ provided by the user 'A. Pine' ( https://stackoverflow.com/u/5583602/ ) 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: selector is not a known element Angular 9 custom library

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.
---
Troubleshooting the is not a known element Error in Angular 9 Custom Libraries

Creating a custom library in Angular can be an exciting and rewarding endeavor. However, many developers encounter the frustrating is not a known element error when trying to implement components from that library. Don't worry—you're not alone! This guide will walk you through the steps to create a custom library and how to effectively troubleshoot this common issue.

Understanding the Problem

Let's break down the problem. You are building an Angular 9 custom library that includes both a service and a component, but upon following certain steps, you encounter the error that indicates your component is not recognized. This is a frequent obstacle for Angular developers, especially those working with libraries.

Steps to Reproduce the Error

To help clarify the path to the error, here’s how you likely reached it:

Create a New Example Project:

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

Navigate into Your Project and Generate a New Library:

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

Generate a New Application:

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

Build the Library:

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

Importing the Module into Your Application:
You should then import your library module in the application’s app.module.ts:

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

Add the Component in Your App Component:
Lastly, in your app.component.ts, you’ll need to embed your custom component:

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

Upon following these steps, if you try to run your application, you may receive an error stating that lib-example-lib is not a known element.

The Solution

Fortunately, you can often resolve this issue with a simple fix: reinstall the node modules. This was the exact solution for many developers facing the same troubling error. Here's how to do it:

Delete the Current Node Modules:
Running the following command will completely remove the existing node_modules directory:

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

Reinstall Packages:
After removing the node_modules, reinstall the packages using:

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

Rebuild Your Project:
After reinstalling, try to build your library and run your application again. The error should be resolved, and your component should now be recognized.

Summary

Creating an Angular 9 custom library can lead to challenges, with the is not a known element error being one of the most common. By carefully following the steps outlined above and troubleshooting issues by reinstalling your packages, you can avoid many potential headaches.

Always remember that rebuilding and reinstalling dependencies can often clear up issues with component recognition. Good luck with your Angular projects, and happy coding!