Скачать или смотреть How to Individually Update Textarea Rows in a ReactJS Component

Discover how to handle individual textarea row updates in ReactJS components effectively. Learn through a coding example that makes your text areas responsive and user-friendly.
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This video is based on the question https://stackoverflow.com/q/73442339/ asked by the user 'Ezz Redfox' ( https://stackoverflow.com/u/9243572/ ) and on the answer https://stackoverflow.com/a/73442518/ provided by the user 'Ezz Redfox' ( https://stackoverflow.com/u/9243572/ ) at 'Stack Overflow' website. Thanks to these great users and Stackexchange community for their contributions.

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Introduction

If you're working with ReactJS and have a table of text areas that you want to expand when clicked, you might run into a common problem. Suppose you want each textarea to expand to 10 rows individually when clicked, and then return to 1 row when it loses focus. The challenge arises when you place these text areas inside an array.map function; click on any textarea, and you'll find all of them expand simultaneously.

In this guide, we'll show you how to achieve the desired functionality using ReactJS by managing the state of each textarea individually. We'll delve into a practical solution to ensure that only the clicked textarea expands, while others remain unaffected.

Problem Explanation

The Issue

Here's the problem you might encounter:

You want text areas to expand on click and shrink back on blur.

When you use array.map to render multiple text areas, all text areas respond to a single click, causing them all to expand.

Typical Snippet

Here's how the basic structure might look:

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

With the above code, clicking any textarea updates inputRows for all instances, causing them to behave identically.

Solution Overview

To solve this problem, we will maintain a separate state for each textarea by leveraging unique identifiers. We'll use the c.key as an identifier for each textarea during mapping. This way, we can ensure that the clicked textarea is the only one that expands.

Implementing the Solution

Step 1: Define State Variables

First, define two states: one for keeping track of which textarea is selected and another for the number of rows.

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

Step 2: Create an Update Function

Next, create an update function that sets the selected textarea key and the number of rows.

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

Step 3: Update the Mapping Function

Within the map function, use the updated row logic to control the rendering of each textarea based on its unique key. Here's the revised mapping structure:

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

Breakdown of Changes

Identify Each Textarea:

Using selectedRow to track which textarea is currently selected.

Conditionally Set Rows:

In the rows attribute, we now conditionally set the number of rows based on whether the c.key matches selectedRow.

Update Logic:

The click and blur handlers now call updateRows with the unique key and desired row number.

Conclusion

By implementing these changes, you ensure that only the clicked textarea expands to 10 rows and contracts when blurred. This approach enhances the usability of your component, allowing for a more intuitive user experience.

If you're tackling a similar problem with ReactJS, consider managing component state in this way to individually control behaviors without affecting other components. Happy coding!