Скачать или смотреть How to Dynamically Assign an onChange Event to Multiple Elements in Hyperscript

Discover an effective method to dynamically assign an `onChange` event to multiple elements using Hyperscript, simplifying your code and enhancing functionality.
---
This video is based on the question https://stackoverflow.com/q/78200930/ asked by the user 'efsant0s' ( https://stackoverflow.com/u/8271313/ ) and on the answer https://stackoverflow.com/a/78203185/ provided by the user 'efsant0s' ( https://stackoverflow.com/u/8271313/ ) 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, comments, revision history etc. For example, the original title of the Question was: Hyperscript - How do i assign an event to a found element?

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.
---
Dynamically Assigning onChange Events in Hyperscript

If you’re working with forms in JavaScript, you might find yourself needing to attach event listeners to multiple elements based on user actions. This becomes quite essential when you're dealing with dynamically generated inputs. In this guide, we will address a common challenge: how to assign an event to a found element using Hyperscript. Let’s dive into the problem and explore a solution that simplifies your code and enhances functionality.

The Problem

You start with a specific event for an individual input element that works flawlessly. For instance, you might have this code managing the onChange event for a VAT number input:

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

While this works perfectly, the real challenge arises when you want to apply this behavior dynamically to several elements. You’ve already set up a structure to identify these elements based on specific criteria:

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

While this was a great start, you hit a roadblock when you tried to assign the onChange event dynamically:

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

Unfortunately, this approach didn’t yield the desired results, and you were looking for a simpler way to handle this.

The Solution

After some experimentation, a more efficient approach emerged. Instead of trying to set an event on each filtered element directly, you can listen for changes at the parent level (the containing div), which will then intelligently filter the events that bubble up. Here’s how the code looks with the new approach:

Updated Code

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

Breakdown of the Code

Event Listening: By moving the event listener to the div, we ensure that any changes within its scope are captured. This allows us to respond to changes on any of the child input elements.

Filtering Logic: The condition if event.srcElement.name.split('][').length > 1 checks if the name of the input element indicates it's part of the group you’re interested in. This prevents handling unrelated inputs.

Constructing the Input Target: Once we know which input triggered the change, we construct the name of the target input by appending ['updated'] to the original input's name.

Updating the Target Input: If the target element exists, we create a timestamp and update the target’s value with the formatted date string.

Conclusion

By switching to a parent-level event listener with a filtering approach, we simplify the event assignment significantly. This methodology not only reduces code complexity but also enhances performance and maintainability. Hyperscript makes event handling intuitive, and with this strategy, you can easily manage multiple dynamic inputs without hassle.

Implementing this solution helps ensure your forms behave predictively and provides users with relevant feedback in real-time. Enjoy coding with Hyperscript!