add eventHandler after component mounted

[IndexXuan]

What problem does this feature solve?

I am writing VCA called useEventListener，which can be used to addEventListener with native HTML element and $on with Vue Component(2.0 @vue/composition-api)。while in Vue 3.0, there are no $on any more and cannot add new eventHandler after component mounted(e.g. with component ref)

What does the proposed API look like?

<el-button @click="handleClick">click</el-button>，then we can use handleClick
but with
<el-button ref="buttonRef">click me</el-button>

useEventListener('click', evt => alert(1), false, buttonRef) // cannot get buttonRef.$on or set buttonRef.onClick(onXXX) in 3.0

readonly proxy can set onXXX instead of reject with warning message

[posva]

See https://v3.vuejs.org/guide/migration/events-api.html#overview

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Hi, thanks for your interest but Github issues are for bug reports and feature requests only. You can ask questions on the forum, the Discord server or StackOverflow.

[IndexXuan]

@posva bro, I know use other event emitter instead of new Vue. It is feature, not question

buttonRef.$props.onClick = evt => alert(1) not work because of code
https://github.com/vuejs/vue-next/blob/f316a332b055d3f448dc735365551d89041f1098/packages/reactivity/src/baseHandlers.ts#L200

It means if we want add eventHandler, the only way is @click in template, we cannot do the same thing when we got buttonRef in setup. any way ? But in 2.0 is OK

[IndexXuan]

In native Dom, we can onclick="handleClick" or we can dom.addEventListener as we want

[leopiccionia]

Have you tried something like buttonRef.$el.addEventListener('click', handleClick)?

[IndexXuan]

@posva this is for component container listener，not component emitted listener

[posva]

The components no longer implement that API: https://v3.vuejs.org/guide/migration/events-api.html#overview it went through an RFC vuejs/rfcs#118

[IndexXuan]

@posva no way to listen component emitted inside setup？very sad ...

[IndexXuan]

it should be buttonRef.onClick = comp emitted click event

[IndexXuan]

#2184
@posva Hi Bro, please review mine