How can I destroy a cached Vue component from keep-alive? - vue.js

Question

My Vue app has a dynamic tabs mechanism.
Users can create as many tabs as the want on the fly, each tab having its own state (eg "Pages").
I am using the <keep-alive> component to cache the different pages.
<keep-alive include="page">
<router-view :key="$route.params.id" />
</keep-alive>
But users can also "close" individual tab. As pages tend to store a lot of datas, I would like to delete the according page component from the cache, as the user close the tab.
How can I programmatically destroy a cached component inside keep-alive ?

Answer 1

You can call this.$destroy() before user close the tab and delete all of data and event binding in that one.

Answer 2

If you don't mind losing the state when a tab is added/removed, then you can try these:
Use v-if and turn off the keep-alive component and turn it back on in
nextTick
Use v-bind on the include list, and remove "page" and add it
back in nextTick

Answer 3

<keep-alive :include="cachedViews">
<router-view :key="key" />
</keep-alive>
cachedViews is the array of the route component name
First when create a tab, cachedViews push the cached route name, when you switch the opened tab, the current route is cached.
Second when close the tab, cachedViews pop the cached route name, the route
component will destroyed.

Answer 4

There is no built-in function in keep-alive which allows you to clear a specific component from the cache.
However, you can clear the cache from the VNode directly inside the component you want to destroy by calling this function :
import Vue, { VNode } from 'vue'
interface KeepAlive extends Vue {
cache: { [key: string]: VNode }
keys: string[]
}
export default Vue.extend({
name: 'PageToDestroy',
...
methods: {
// Make sure you are not on this page anymore before calling it
clearPageFromKeepAlive() {
const myKey = this.$vnode.key as string
const keepAlive = this.$vnode.parent?.componentInstance as KeepAlive
delete keepAlive.cache[myKey]
keepAlive.keys = keepAlive.keys.filter((k) => k !== myKey)
this.$destroy()
}
},
})
For me, it doesn't cause any memory leaks and the component is not in the Vue.js devtools anymore.

Answer 5

based on the answer of #feasin, here is the setup I am using
template
<router-view v-slot="{ Component }">
<keep-alive :include="cachedViews">
<component :is="Component" :key="$route.fullPath" />
</keep-alive>
</router-view>
script
import { ref, inject, watch } from "vue";
export default {
components: { CustomRouterLink },
setup() {
const cachedViewsDefault = ["Page1", "Page1", "Page3"];
var cachedViews = ref([]);
const auth = inject("auth");
// check whether user is logged in (REACTIVE!)
const isSignedIn = auth.isSignedIn;
// set the initial cache state
if (isSignedIn.value) {
cachedViews.value = cachedViewsDefault;
}
// clear the cache state
watch(isSignedIn, () => {
if (!isSignedIn.value) {
cachedViews.value = [];
} else {
cachedViews.value = cachedViewsDefault;
}
});
return {
cachedViews,
};
},
};
First I set the initial cached views value based on whether the user is logged in or not.. After the user logs-out I simply set the array value to an empty array.
When the user logs back in - I push the default array keys back into the array.
This example of course does not provide the login/logout functionality, it is only meant as a POC to to the solution proposed by the #feasin (which seems like a good approach to me)
Edit 19.01.2022
I now understand the shortcomings of such approach. It does not allow to gradually destroy a certain component. Given that we have a component named Item and it's path is Item/{id} - there is currently no native way (in Vuejs3) to remove, let's say a cached item with Id = 2. Follow up on this issue on the Github: https://github.com/vuejs/rfcs/discussions/283
Edit 20-21.01.2022
Note that you have to use the computed function for inclusion list. Otherwise the component will not ever be unmounted.
Here is the fiddle with the problem: https://jsfiddle.net/7f2d4c0t/4/
Here's fiddle with the fix: https://jsfiddle.net/mvj2z3pL/
return {
cachedViews: computed(() => Array.from(cachedViews.value)),
}