I can't call child component method in parent component in Vue3
In Vue2, I can call child component method like this
this.$root.$refs.ChildComponent.methodName()
But in Vue3, I receive a error like this
runtime-core.esm-bundler.js:218 Uncaught TypeError: Cannot read properties of undefined (reading 'methodName')
defineExpose could do the magic. You could do something like this:
// in Parent
<template>
<ChildComponent ref="myChild"/>
</template>
<script>
const myChild = ref(null);
function() {
myChild.childMethod();
}
</script>
// ChildComponent
<template> ... </template>
<script setup>
function childMethod() {
// do something
}
defineExpose({
childMethod
});
</script>
You might want to pass in a prop to the child, and react to a change-event by calling the method. This could look something like this:
<!-- Parent.vue -->
<script setup>
/* declare invokeChildMethod */
</script>
<template>
<Child :prop="invokeChildMethod" />
</template>
As can be seen in the code below, when the variable (here called invokeChildMethod) changes (in the parent), an event for the child will be fired.
Here's a resource on watching props in Vue3.
In addition to nocrash9000's answer (which did the trick for me), do not forget to add the import statement
import { defineExpose } from 'vue'
Related
I have a very simple vuejs component like this :
<template>
<h1>{{title}}</h1>
</template>
<script setup>
const props = defineProps({
title: String,
})
</script>
title is correctly interpreted to the prop being passed to this component. Out of curiosity: why do I not need to do {{props.title}} for this to work.
This only reason I now write {{props.title}} is in order to do away with lint errors.
We would like to pass props to custom elements that uses createApp
// index.html
<div id="my-root">
<my-element prop1="abc"></my-element>
</div>
// my-element.vue
<script lang="ts" setup>
const props = defineProps<{ prop1: number }>();
</script>
<template>
{{props.prop1}}
</template>
This works fine, but as our custome element get bigger we would like to register components and use e.g pinia and other tools. Do use those we need to add createApp and mount it. But then prop1 is always undefined
// main.ts
import ...<lots of imports>
import AppCe from "./AppWebComponent.ce.vue";
import { createPinia } from "pinia";
// Adding code below is causing prop1 to be undefined - if we skip this part, prop1 works fine
const pinia = createPinia();
const app = createApp(App);
app.use(pinia).use(ConfirmDialog);
app.component(...<lots of components>);
app.mount("#my-root");
const ceApp = defineCustomElement(AppCe);
customElements.define("my-element", ceApp);
update:
Here's a sample without: https://stackblitz.com/edit/vue3-script-setup-with-vite-56rizn?file=src/my-element/my-element-main.js
And here's a sample with the createApp: https://stackblitz.com/edit/vue3-script-setup-with-vite-gtkbaq?file=index.html
Any idea on how we could solve this?
We have a fallback, that is to do a getElementById and read the attribute value in the mounted callback - but that is not an optimal solution.
Thanks for any ideas!
update2:
Here's an attempt using #duannex suggestion. We're getting closer, the app is availible, components registered, but still no sigar. : https://stackblitz.com/edit/vue3-script-setup-with-vite-ofwcjt?file=src/my-element/defineCustomElementWrapped.js
Based on update2 with the wrapped defineCustomElement; Just pass the props to the render function:
render() {
return h(component, this.$props)
},
https://stackblitz.com/edit/vue3-script-setup-with-vite-vfdnvg?file=src/my-element/defineCustomElementWrapped.js
I have a vue3 app, and one of the child component uses vue-draggable.
In the parent component I have an object (let's call it myJson) which propagates to child component with props.
So far it works as expected.
However, when adding 'KeepAlive' to the parent component, every time I drag the items, myJson is set to the drag event instead of the origin data it had.
It still occures even if I pass to the child component a copy of myJson (with JSON parse-JSON stringify). See details below
parent component:
<template>
<KeepAlive>
<component :is="activeComponent" :my-json="myJson" />
</KeepAlive >
</template>
data: () => ({
myJson: { ...someData }
})
mid component:
<template>
<list-items :items="items" />
</template>
<script>
export default {
components: { ListItems },
computed: {
items() {
return JSON.parse(JSON.stringify(this.myJson.value.items))
}
},
}
</script>
child component (ListItems):
<template>
<draggable
v-model="items"
animation="100"
handle=".dnd-handle"
item-key="product"
class="items-list"
#start="drag=true"
#end="drag=false"
>
<template #item="{ element, index }">
{{element}}
</template>
</draggable>
</template>
<script>
import draggable from 'vuedraggable'
export default {
components: { draggable },
props: ['items'],
}
</script>
The items are displayed correctly in the component.
Before dragging, myJson is an object with my data.
After dragging myJson is an event.
Any idea?
vuedraggable version is 4.1.0
--UPDATE--
In parent component there is a function "update", which gets value and updates myJson.
methods: {
update (value) {
myJson = value
}
}
I found out that every time I drag, there is a call to this function with the dragging event as value, even when I try to catch the draggable events. Thats why myJson gets wrong value.
My problem was solved when I changed the function's name. But anyone knows why this happens?
How can I get the current route using useRoute for a component that's outside of the <router-view />? Is this possible?
Breadcrumbs.vue
<script setup>
import {useRoute} from 'vue-router'
const route = useRoute()
console.log(route.name) // undefined
</script>
App.vue
<template>
<Breadcrumbs />
<router-view />
</template>
The alternative is that I have to put <Breadcrumbs /> at the top of every single view component, and I was hoping to avoid that and instead just include it once in my App.vue
route.name is undefined in your example because that's the initial value when the component is rendered before the route has resolved.
For the component to reactively update based on the current route, use a watcher (e.g., watch or watchEffect):
import { watchEffect } from 'vue'
import { useRoute } from 'vue-router'
const route = useRoute()
watchEffect(() => {
console.log(route.name)
})
demo
In your main file, try to mount app like this
router.isReady().then(() => {
app.mount('#app');
});
then useRoute() should be ready in your component
I want to achieve communication between child parent with Polymer element.
Here my index.html
<proto-receiver data="message">
<proto-element data="message"></proto-element>
</proto-receiver>
Both element have their respective "data" property
properties: {
data: {
value: 'my-data',
notify: true,
}
},
In proto-receiver, which is the parent I update "data" by handling simple click
<template>
<span on-tap="onClick">proto receiver: {{data}}</span>
<content></content>
</template>
onClick: function () {
this.data = 'new-message';
},
I want the change to be propagate to the child element as well, as it mentioned here.
I achieve this by passing a setter in my child element and called it like this. Which is, I guess, not the way it should be done.
Polymer.Base.$$('body').querySelector('proto-element').setData(this.data);
What I'm doing wrong
Thanks
UPDATE:
For those coming here. The proper way of doing this is by using Events.
Polymer 1.x
this.fire('kick', {kicked: true});
Polymer 2.x (simple javascript)
this.dispatchEvent(new CustomEvent('kick', {detail: {kicked: true}}));
In both case the receiver should implement the regular addEventListener
document.querySelector('x-custom').addEventListener('kick', function (e) {
console.log(e.detail.kicked); // true
})
To provide a concrete example to Scott Miles' comments, if you can wrap your parent and child elements in a Polymer template (such as dom-bind or as children to yet another Polymer element), then you can handle this declaratively. Check out the mediator pattern.
parent element:
<dom-module id="parent-el">
<template>
<button on-tap="onTap">set message from parent-el</button>
<p>parent-el.message: {{message}}</p>
<content></content>
</template>
<script>
Polymer({
is: 'parent-el',
properties: {
message: {
type: String,
notify: true
}
},
onTap: function() {
this.message = 'this was set from parent-el';
}
});
</script>
</dom-module>
child element:
<dom-module id="child-el">
<template>
<p>child-el.message: {{message}}</p>
</template>
<script>
Polymer({
is: 'child-el',
properties: {
message: {
type: String,
notify: true
}
}
});
</script>
</dom-module>
index.html:
<template is="dom-bind" id="app">
<parent-el message="{{message}}">
<child-el message="{{message}}"></child-el>
</parent-el>
</template>
<script>
(function(document) {
var app = document.querySelector('#app');
app.message = 'this was set from index.html script';
}) (document);
</script>
JS Bin
I was facing same issue and got solution for it and fixed it as below
this.fire('iron-signal', {name: 'hello', data: null});
You can refer this iron-signals you will get the solution which you are looking for its basically event fire from any element to another
Hope this will help you
Polymer iron signals