v-ripple on router-link: mdc classes get lost

[meibegger]

Describe the bug
When adding v-ripple to router-link, the ripple only works once, because the mdc- classes vanish on route-change

Desktop:

• OS: Mac
• Browser Current Firefox & Chrome

Possible fix
I fixed this by using a MutationObserver and re-adding the previous classes.

interface MDCRippledElement extends HTMLElement {
  mdcRipple: MDCRipple
}

const mutationConfig: MutationObserverInit = {
  attributeFilter: ['class'],
  attributes: true,
  attributeOldValue: true,
}
const observer = new MutationObserver(mutationCallback)

function mdcClasses(className: string | null) {
  return className ? className.match(/mdc-[a-z-]+/g) || [] : []
}

function mutationCallback(mutationList: MutationRecord[]) {
  mutationList.forEach(({ target: el, oldValue }) => {
    const target = el as MDCRippledElement
    // re-add the lost mdc-classes
    const currentMDCClasses = mdcClasses(target.className)
    if (!currentMDCClasses.length) {
      const oldMDCClasses = mdcClasses(oldValue)
      target.classList.add(...oldMDCClasses)
    }
  })
}
...
bind() {
  observer.observe(el, mutationConfig)
}

(this will not work, if the customized modifier is used))

[tychenjiajun]

@meibegger Before I find the cause, you can use the scope slot in <router-link>.

<router-link
  to="/about"
  v-slot="{ href, route, navigate, isActive }"
>
  <a v-ripple :active="isActive" :href="href" @click="navigate">{{ route.fullPath }}</a>
</router-link>

This might be easier than using the MutationObserver.

[meibegger]

Thank you!

But as soon as you toggle the class on the link, you get the same problem:

<a v-ripple :class="{active: isActive}" :href="href" @click="navigate">{{ route.fullPath }}</a>

So the workaround would be this https://router.vuejs.org/api/#v-slot-api-3-1-0