Vue-next: ref doesn't work properly with v-for together

[Jinjiang]

Version

3.0.0-beta.10

Reproduction link

https://codesandbox.io/s/goofy-yalow-d0x6e?file=/src/App.vue

Steps to reproduce

<template>
  <span v-for="n in 10" ref="x">{{ n }}</span>
</template>

<script>
export default {
  mounted() {
    console.log(this.$refs.x);
  }
}
</script>

What is expected?

print an array of all spans

What is actually happening?

the last span

---

https://vuejs.org/v2/api/#ref

When used on elements/components with v-for, the registered reference will be an Array containing DOM nodes or component instances.

[yyx990803]

Vue 3 no longer has special behavior for v-for refs: https://composition-api.vuejs.org/api.html#template-refs

[yyx990803]

Actually, we may need to detect non composition api usage for backwards compat. Or we need an RFC to officially deprecate this (I never considered it good practice anyway, and it creates a TON of complexity when used inside nested v-fors.)

[Jinjiang]

Gotcha. My quick idea is introducing another refs="x" for v-for which equals to :ref="el => $refs.x[i] = el. So it’s easy to code-mod and deprecate further I guess. Maybe will propose something like that later to RFCs. Thanks.

[sagalbot]

It's worth noting that the current v3 docs do explicitly note support for v-for with refs:

When ref is used together with v-for, the ref you get will be an array containing the child components mirroring the data source.

https://v3.vuejs.org/guide/component-template-refs.html

If this should be changed to reflect the current status I'm happy to PR.

[syuilo]

Is there any migration strategy for about this?

[LinusBorg]

Actually, we may need to detect non composition api usage for backwards compat. Or we need an RFC to officially deprecate this (I never considered it good practice anyway, and it creates a TON of complexity when used inside nested v-fors.)

@yyx990803 We actually can do the same thing we recommend for the composition with the options API:

Example: https://jsfiddle.net/Linusborg/xjcbyw2f/1/

This should in theory also allow people to come up with a strategy for nested v-for situations (which, I agree, are a complexity nightmare)

@syuilo That should work as a migration strategy I think.

@vuejs/docs Can we add this example to the migration guide for Options-API users?