<div>
<button #click="$refs.cart.open()">open</button>
<drawer></drawer>
</div>
ref=cart is inside <drawer>, can I call from that button? how?
---edited---
---edited solve with vuex---
root template
toggle() {
this.$store.dispatch('toggle', {
toggle: 'close'
}).then(() => {
this.$store.dispatch('toggle', {
toggle: 'open'
})
})
}
inside drawer
computed: {
toggle() {
return this.$store.state.toggle
}
},
watch: {
toggle(val) {
if (val == 'open') this.$refs.cart.open()
}
}
A simple solution (not the best) would be to just use a Vue event bus to communicate between components here. Quasar has a global event bus (http://quasar-framework.org/api/js-events.html).
Best solution would be to use Vuex but of course, not if you need it just for this.
Vue references are tricky and are not always ready to use. The explanation is long and has to do with how Vue renders.
Related
Destroyed hook is called later than i need.
I tried to use beforeDestroy instead of destroy, mounted hook instead of created. The destroy hook of previous components is always called after the created hook of the components that replaces it.
App.vue
<div id="app">
<component :is="currentComponent"></component>
<button #click="toggleComponent">Toggle component</button>
</div>
</template>
<script>
import A from './components/A.vue';
import B from './components/B.vue';
export default {
components: {
A,
B
},
data: function(){
return {
currentComponent: 'A'
}
},
methods: {
toggleComponent() {
this.currentComponent = this.currentComponent === 'A' ? 'B' : 'A';
}
}
}
</script>
A.vue
<script>
export default {
created: function() {
shortcut.add('Enter', () => {
console.log('Enter pressed from A');
})
},
destroyed: function() {
shortcut.remove('Enter');
}
}
</script>
B.vue
<script>
export default {
created: function() {
shortcut.add('Enter', () => {
console.log('Enter pressed from B');
})
},
destroyed: function() {
shortcut.remove('Enter');
}
}
</script>
Result:
// Click Enter
Enter pressed from A
// now click on toggle component button
// Click Enter again
Enter pressed from A
Expected after the second enter to show me Enter pressed from B.
Please don't show me diagrams with vue's lifecycle, i'm already aware of that, I just need the workaround for this specific case.
Dumb answers like use setTimeout are not accepted.
EDIT: Made some changes to code and description
If you are using vue-router you can use router guards in the component (as well as in the router file) where you have beforeRouteLeave obviously only works where there is a change in route, see here:
https://router.vuejs.org/guide/advanced/navigation-guards.html#in-component-guards
I have been reading lots of articles about this, and it seems that there are multiple ways to do this with many authors advising against some implementations.
To make this simple I have created a really simple version of what I would like to achieve.
I have a parent Vue, parent.vue. It has a button:
<template>
<div>
<button v-on:click="XXXXX call method in child XXXX">Say Hello</button>
</div>
</template>
In the child Vue, child.vue I have a method with a function:
methods: {
sayHello() {
alert('hello');
}
}
I would like to call the sayHello() function when I click the button in the parent.
I am looking for the best practice way to do this. Suggestions I have seen include Event Bus, and Child Component Refs and props, etc.
What would be the simplest way to just execute the function in my method?
Apologies, this does seem extremely simple, but I have really tried to do some research.
Thanks!
One easy way is to do this:
<!-- parent.vue -->
<template>
<button #click="$refs.myChild.sayHello()">Click me</button>
<child-component ref="myChild" />
</template>
Simply create a ref for the child component, and you will be able to call the methods, and access all the data it has.
You can create a ref and access the methods, but this is not recommended. You shouldn't rely on the internal structure of a component. The reason for this is that you'll tightly couple your components and one of the main reasons to create components is to loosely couple them.
You should rely on the contract (interface in some frameworks/languages) to achieve this. The contract in Vue relies on the fact that parents communicate with children via props and children communicate with parents via events.
There are also at least 2 other methods to communicate when you want to communicate between components that aren't parent/child:
the event bus
vuex
I'll describe now how to use a prop:
Define it on your child component
props: ['testProp'],
methods: {
sayHello() {
alert('hello');
}
}
Define a trigger data on the parent component
data () {
return {
trigger: 0
}
}
Use the prop on the parent component
<template>
<div>
<childComponent :testProp="trigger"/>
</div>
</template>
Watch testProp in the child component and call sayHello
watch: {
testProp: function(newVal, oldVal) {
this.sayHello()
}
}
Update trigger from the parent component. Make sure that you always change the value of trigger, otherwise the watch won't fire. One way of doing this is to increment trigger, or toggle it from a truthy value to a falsy one (this.trigger = !this.trigger)
I don't like the look of using props as triggers, but using ref also seems as an anti-pattern and is generally not recommended.
Another approach might be: You can use events to expose an interface of methods to call on the child component this way you get the best of both worlds while keeping your code somehow clean. Just emit them at the mounting stage and use them when pleased. I stored it in the $options part in the below code, but you can do as pleased.
Child component
<template>
<div>
<p>I was called {{ count }} times.</p>
</div>
</template>
<script>
export default {
mounted() {
// Emits on mount
this.emitInterface();
},
data() {
return {
count: 0
}
},
methods: {
addCount() {
this.count++;
},
notCallable() {
this.count--;
},
/**
* Emitting an interface with callable methods from outside
*/
emitInterface() {
this.$emit("interface", {
addCount: () => this.addCount()
});
}
}
}
</script>
Parent component
<template>
<div>
<button v-on:click="addCount">Add count to child</button>
<child-component #interface="getChildInterface"></child-component>
</div>
</template>
<script>
export default {
// Add a default
childInterface: {
addCount: () => {}
},
methods: {
// Setting the interface when emitted from child
getChildInterface(childInterface) {
this.$options.childInterface = childInterface;
},
// Add count through the interface
addCount() {
this.$options.childInterface.addCount();
}
}
}
</script>
With vue 3 composition api you can do it like this:
Parent.vue
<script setup lang="ts">
const childRef = ref()
const callSayHello = () => {
childRef.value.sayHello()
}
</script>
<template>
<child ref="childRef"></child>
</template>
<style scoped></style>
Child.vue
<script setup lang="ts">
const sayHello = () => {
console.log('Hello')
}
defineExpose({ sayHello })
</script>
<template></template>
<style scoped></style>
I am not sure is this the best way. But I can explain what I can do...
Codesandbox Demo : https://codesandbox.io/s/q4xn40935w
From parent component, send a prop data lets say msg. Have a button at parent whenever click the button toggle msg true/false
<template>
<div class="parent">
Button from Parent :
<button #click="msg = !msg">Say Hello</button><br/>
<child :msg="msg"/>
</div>
</template>
<script>
import child from "#/components/child";
export default {
name: "parent",
components: { child },
data: () => ({
msg: false
})
};
</script>
In child component watch prop data msg. Whenever msg changes trigger a method.
<template>
<div class="child">I am Child Component</div>
</template>
<script>
export default {
name: "child",
props: ["msg"],
watch: {
msg() {
this.sayHello();
}
},
methods: {
sayHello() {
alert("hello");
}
}
};
</script>
This is an alternate take on Jonas M's excellent answer. Return the interface with a promise, no need for events. You will need a Deferred class.
IMO Vue is deficient in making calling child methods difficult. Refs aren't always a good option - in my case I need to call a method in one of a thousand grandchildren.
Parent
<child :getInterface="getInterface" />
...
export default {
setup(props) {
init();
}
async function init() {
...
state.getInterface = new Deferred();
state.childInterface = await state.getInterface.promise;
state.childInterface.doThing();
}
}
Child
export default {
props: {
getInterface: Deferred,
},
setup(props) {
watch(() => props.getInterface, () => {
if(!props.getInterface) return;
props.getInterface.resolve({
doThing: () => {},
doThing2: () => {},
});
});
}
}
I've seen this question multiple times, but without a good response
I have a topmenu with links and I want to trigger a function when I click the link of the page that I'm on right now
How do I achieve this?
Remember the in-component guards wont trigger because the route does not change
You would want to trigger a function on all links and trigger the navigate from in there passed by a param.
Then check if the current page URL matches the passed param.
E.g.
if (this.$router.currentRoute == 'param passed') {
return someOtherFucntion();
}
return this.$router.push('param passed');
Its called programmatic navigation you can see more here.
https://router.vuejs.org/guide/essentials/navigation.html#programmatic-navigation
I believe I found a more elegant solution
I made a wrapper for links
<template>
<a :href="resolvedRoute.route.fullPath" :class="{ 'is-active': resolvedRoute.route.name == $route.name }" #click.prevent="clicked">
<slot></slot>
</a>
</template>
<script>
import EventBus from '#/event-bus'
export default {
name: 'menu-link',
props: {
to: {
type: Object,
default: {}
}
},
computed: {
isExactActive(){
return this.$route.fullPath == this.resolvedRoute.route.fullPath
},
resolvedRoute(){
return this.$router.resolve(this.to)
}
},
methods: {
clicked(){
if(this.isExactActive)
return EventBus.$emit('page-reload', this.resolvedRoute.route)
this.$router.push(this.to)
}
}
}
</script>
Then a simple mixin
import EventBus from '#/event-bus'
export default {
mounted(){
EventBus.$on('page-reload', this.checkPageReload)
},
beforeDestroy(){
EventBus.$off('page-reload', this.checkPageReload)
},
methods: {
checkPageReload(route){
if(route.name == this.$options.name && this.pageReload){
EventBus.$emit('page-loading', true)
this.pageReload(route)
}
}
}
}
I believe this is the optimal solution. I'll just have to replace router-link with menu-link
I have a special application where I would like to run a method on every component when it is mounted. So I could have the method as a global mixin or something and then simply do..
mounted(){
this.mySpecialMethod();
}
However, I was wondering if it is possible to simply extend Vues mounted hook so the method is always run on every component when it is mounted. I have not been able to find in info on this.
If you really want to have everything call your mounted hook, you can use a global mixin.
Below, we have the mixin myMixin that will log to console every time something is mounted or destroyed. When you run the example, you can see that every time the plus button is clicked, it runs both the component's mounted hook as well as the mixin's hook.
If you want to extend this so that it can be reusable as a library, you can create a plugin out of it.
const foo = {
template: "<div #click='onClick'>hello</div>",
mounted() {
console.log("Foo's mounted");
},
methods: {
onClick() {
console.log("click");
}
}
}
const myMixin = {
mounted() {
console.log("I've been mounted");
},
destroyed() {
console.log("I've been destroyed");
}
};
Vue.mixin(myMixin);
const app = new Vue({
el: "#app",
data() {
return {
foos: []
};
},
components: {
foo
},
methods: {
add() {
this.foos.push("fizz");
},
remove() {
this.foos.pop();
}
}
});
<script src="https://cdn.jsdelivr.net/npm/vue"></script>
<div id="app">
<button #click="add()">+</button><button #click="remove()">-</button>
<ul>
<li v-for="f in foos">
<foo></foo>
</ul>
</div>
I have a custom vue directive.
Vue.directive('click-outside', {
bind: function (el, binding, vnode) {
document.addEventListener(clickHandler, (event) => {
const clickedInsideDropdown = el.contains(event.target);
if (!clickedInsideDropdown && el.classList.contains(openClass)) {
vnode.context.$emit(binding.expression);
}
});
}
});
I then initialize it with the dropdown template:
<template>
<div class="dropdown" :class="{ '-is-open': open }" v-click-outside="close">
<span #click="toggle">
<slot name="toggle"></slot>
</span>
<slot name="menu"></slot>
</div>
</template>
The supporting logic is functioning as expected as well:
<script>
export default {
data: function () {
return {
open: false
}
},
methods: {
close: function () {
this.open = false;
console.log('close');
},
toggle: function () {
this.open = !this.open;
console.log('toggle');
}
}
}
</script>
The Problem
The event should fire when the current dropdown _is open and none of the items inside of it are clicked - which is does (console logging confirms this). However, the $emit is not triggering the close method for some reason.
The event is being emitted in the Vue devtools as expected.
Vue version 2.5.3
Credits to Linus Borg who answered my question for me on the forum. Was just understanding the purpose of events incorrectly.
Events are usually used to communicate from a child component to a parent component, so triggering an event ‘close’ in a componet will not run a method of that name in that component.
If you want that, you have to actually register a listener to that event:
created () {
this.$on('close', this.close /*the name of the method to call */)
}
However, this isn’t really necessary in your case. you are already passing the close method to the directive, so you can run it directly:
Vue.directive('click-outside', {
bind: function (el, binding, vnode) {
document.addEventListener(clickHandler, (event) => {
const clickedInsideDropdown = el.contains(event.target);
if (!clickedInsideDropdown && el.classList.contains(openClass)) {
binding.value()
// alternartively, you could also call the method directly on the instance, no need for an event:
vnode.context.[expression]()
// but that wouldn't really be elegant, agreed?
}
});
}
});