How to Display ngFor Keys and Values Including Nested Data in Angular

Learn how to effectively use *ngFor in Angular to display keys and values, including nested objects, using an `isNested` function for better data handling.
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This video is based on the question https://stackoverflow.com/q/66301597/ asked by the user 'ojy2021' ( https://stackoverflow.com/u/15060880/ ) and on the answer https://stackoverflow.com/a/66301971/ provided by the user 'Lukasz Gawrys' ( https://stackoverflow.com/u/15025918/ ) at 'Stack Overflow' website. Thanks to these great users and Stackexchange community for their contributions.

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How to Display ngFor Keys and Values Including Nested Data in Angular

When working with Angular, displaying data dynamically can sometimes lead to unexpected results, especially when dealing with nested objects. If you find yourself struggling to display keys and values correctly from an object that also contains nested data, you're not alone. In this guide, we'll address a common issue encountered with *ngFor in Angular and present a clear solution to help you manage complex data structures effectively.

Understanding the Problem

Let's say you have data structured like this:

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

You want to display this data using the *ngFor directive like so:

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

However, you might notice that when it comes to nested data, such as the items in the extra array, it doesn't display the content properly. Instead, you may see simply Object when it encounters the array. This is because ngFor does not automatically handle nested arrays or objects.

Solution Overview

To effectively display both the keys and values of the main object and any nested data, we'll modify our approach. Below is the step-by-step solution to achieve this.

Step 1: Create a Template for Nested and Non-Nested Items

We will use a combination of *ngFor and an isNested checking function to determine whether or not the current value is additionally an object or an array.

Here's how the updated HTML could look:

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

Step 2: Defining the isNested Function

To help determine if the current value is an object or nested array, we need a helper function. This function can be as simple as checking the type of the value:

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

Summary of Changes

Dynamic Rendering: The modified template allows for dynamic rendering of both the base keys and values as well as any nested data.

Helper Function: The isNested function helps to distinguish between non-nested and nested items.

Improved User Experience: With these changes, users will get a clear and organized view of data, no longer seeing Object displayed for nested items.

Conclusion

In summary, by using a systematic approach to handle both keys and values in Angular, including nested data, we enhance the data display in our applications. The combination of ngFor, conditionals, and helper functions provides a powerful method to manage complex data structures. So next time you face a similar issue with Angular's *ngFor, remember this technique to make your data fully visible and organized.

Now, you're ready to take your Angular project to the next level by effectively displaying both simple and nested data structures! If you have any questions or need further clarification on any part of this solution, feel free to leave a comment below.

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