Fix interoperability issue regarding Event properties

[alecpl]

• make possible to re-set read-only event properties
• use hydrateObj() to set delegateTarget property

Fixes #36207

[GeoSot]

Thank you, @alecpl, for your PR.

Please take under consideration the need of below change (not sure if is needed), and it would be great to support your Pr with the proper tests

function hydrateObj(obj, meta) {
  for (const [key, value] of Object.entries(meta || {})) {
    try {
      obj[key] = value
    } catch {
      Object.defineProperty(obj, key, {
       configurable: true,
        get() {
          return value
        }
      })
    }
  }

  return obj
}

[alecpl]

@GeoSot I considered the change before, but I'm not sure it's really worth it. As for the tests, I'm afraid I will not be able to do that, as I have no idea about bootstrap's tests nor build system.

[GeoSot]

I can help you witting the tests, but at least need a codepen that replicates the issue, you are trying to solve here

[alecpl]

The main issue is if you have an external library like cash-dom that is handling the same event as Bootstrap (e.g. a click handler on a Tab) and is setting the delegateTarget (in this case, but I can imagine other properties with the same issue). Cash-dom makes the delegateTarget property read-only and Bootstrap can't just do event.delegateTarget = something assignment.

The second part of the patch (configurable: true) makes sure that read-only properties set by Bootstrap can be re-set outside.

Now thinking about this, and considering https://github.com/jquery/jquery/blob/5d5ea015114092c157311c4948f7cc3d8c8e7f8a/src/event.js#L306 we might indeed need the change you suggested. I mean it would be nice to be consistent inside Bootstrap and make all event properties read-only, but it may break compatibility with jQuery. I didn't test that.

[GeoSot]

I did the change and added some tests to help. Just to note down here, I am not sure if I have understood the real issue on this situation, and if the proposed solution is valid. So if any other js dev have better knowledge, please d not hesitate to write an opinion

[GeoSot]

@julien-deramond are we going to merge it?