Implementing ng-template in Angular

Learn how to effectively use the `ng-template` directive in Angular to simplify your conditional rendering and avoid duplicated HTML.
---
This video is based on the question https://stackoverflow.com/q/66792324/ asked by the user 'PaulDickson' ( https://stackoverflow.com/u/14775360/ ) and on the answer https://stackoverflow.com/a/66792465/ provided by the user 'Francesco Lisandro' ( https://stackoverflow.com/u/11833410/ ) 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: How do I implement directive (ng-template) in Angular?

Also, Content (except music) licensed under CC BY-SA https://meta.stackexchange.com/help/licensing
The original Question post is licensed under the 'CC BY-SA 4.0' ( https://creativecommons.org/licenses/by-sa/4.0/ ) license, and the original Answer post is licensed under the 'CC BY-SA 4.0' ( https://creativecommons.org/licenses/by-sa/4.0/ ) license.

If anything seems off to you, please feel free to write me at vlogize [AT] gmail [DOT] com.
---
Introduction

When building an Angular application, you might encounter situations where you have similar blocks of HTML for different states of your data. In one example, a developer found themselves duplicating an "else" block in their HTML code due to conditional rendering. This can make our codebase harder to maintain. Thankfully, Angular provides a powerful directive called ng-template that can help us address this problem efficiently.

In this guide, we'll take a closer look at how to implement ng-template in Angular to handle conditional rendering elegantly and avoid unnecessary duplication of code.

Understanding the Problem

Imagine you want to display the size of a file if it is successfully processed or show the progress of a file upload. If neither condition is met, you want to display a fallback message. Here’s a snippet of code to illustrate this:

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

Here, we've duplicated the elseBlock2 for both conditions, which is not ideal. Let's explore how to streamline this implementation using ng-template.

Implementing ng-template

To handle this situation more effectively, you can implement ng-template to avoid duplication and make your code cleaner. Below is a revised version of the previous code that utilizes the ng-template directive:

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

Key Changes Explained

Single Conditional Check: We use a single ng-container that checks if either item.isSuccess or item.progress is true. If both are false, it switches to the elseBlock2 content.

Separated Content Blocks: Inside the conditional ng-container, we have separate ng-container directives for item.isSuccess and item.progress. This keeps the logic clear and organized.

Defining elseBlock2: The content you want to display when both conditions are false is wrapped inside an ng-template identified by the # elseBlock2 reference.

Optional Update: Further Simplification

If you want to further simplify your code, especially if you only want to display the fallback content when neither condition is met, you can implement it like this:

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

Conclusion

Utilizing the ng-template directive in Angular helps reduce the clutter in your HTML by allowing you to manage similar rendering conditions without duplicating code. It not only enhances readability but also makes your Angular components easier to maintain.

In summary, always consider using ng-template for conditional rendering to keep your templates clean and efficient. Happy coding!

Видео Implementing ng-template in Angular канала vlogize