Скачать или смотреть How to Display userName in Angular Material Table

Struggling to show user names in your Angular Material table? Follow this guide to easily display nested JSON data, including handling cases of null values.
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How to Display userName in Angular Material Table: A Step-by-Step Guide

If you're working with Angular and Angular Material, you might have encountered challenges when it comes to displaying data from a JSON structure in a material table. One common issue developers face is not being able to correctly display user information, particularly when it involves nested JSON properties. In this post, we’ll walk through how to display the userName field from a data structure that includes a user node.

Understanding the Problem

Imagine you have a JSON object that contains student records, including information about their user accounts. Here's a simplified version of the JSON data you're working with:

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

In this data:

The first student's user node has a userName.

The second student's user node is null.

When you try to display the userName in your Angular Material table, you might not see any output, especially for the student whose user details are null. Let’s dive into how to properly handle this situation.

Step-by-Step Solution

1. Correctly Accessing Nested Data

The first thing to correct is how you access the userName property. Instead of directly trying to access element.userName, you'll need to navigate through the user node. The correct syntax in your Angular template will look like this:

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

2. Handling Null Values Gracefully

In the code snippet above, we've included the null-safe operator ?.. This operator ensures that if the user node is null, the code won’t throw an error. Instead, it simply results in an empty output for that cell.

Here’s the breakdown of the code:

element.user?.userName: This checks if user exists. If it does, it displays the userName. If user is null, it will not attempt to access userName, thus avoiding any errors.

3. Defining Your Columns

Make sure that you've included the userName in your displayed columns array:

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

4. Rechecking Your Display Column Array

Your displayedColumns should align with the column definitions in your HTML template. Double-check that your column definitions match your data structure to avoid any issues at runtime.

Conclusion

By implementing the changes outlined above, you should now be able to display the userName correctly in your Angular Material table, regardless of whether the user data is populated or null. Keeping in mind the use of the null-safe operator ensures that your application handles potential missing data gracefully without crashing.

Happy coding, and may your Angular journey be less problematic!