VueJS 2 show some HTML if a Function prop was passed - javascript

Question
In VueJS 2 how do you show some HTML if a Function prop was passed to the component.
Example
<template>
<div v-if="backBtn" #click="$emit('backBtn')">Back Button</div>
</template>
<script>
export default {
props: {
backBtn: Function
}
}
</script>
I can do this by passing a separate prop to key the v-if off of but I'm trying to do this will the one prop.
I created a Fiddle for this issue here

that should work,
you can add more definition with !== undefined
<template>
<div v-if="backBtn !== undefined" #click="$emit('backBtn')">Back Button</div>
</template>
<script>
export default {
props: {
backBtn: {
type: Function,
},
}
}
</script>
but as mentioned, that should work already, so you error may be somewhere else.
after seeing your code, I see what the issue is. it's a case issue
use :back-btn instead of :backBtn
this happens only if you're using vue runtime only (without the compilation)
read more here:
https://v2.vuejs.org/v2/guide/installation.html#Runtime-Compiler-vs-Runtime-only
you can solve it also by passing the function only
https://jsfiddle.net/rz6hyd7b/7/
Vue.component('my-btn', {
props: {
backbtn: {
type: Function
}
},
template: `
<div>
<div v-if="backbtn" #click="backbtn">Back Button</div>
</div>
`
})
var vm = new Vue({
el: '#app',
components: 'my-btn',
methods: {
btnClicked: function(){
console.log('adsf')
}
},
template: `
<div>
Show Btn => <my-btn :backbtn="btnClicked"></my-btn>
</br>
Hidden Btn => <my-btn></my-btn>
</div>
`
});

Related

this.$emit() is not a function while trying to change state in parent component from child in composition API in vue 3

//Parent component
<template>
<childComp #onchangeData='changeData' />
</template>
<script>
setup() {
const state = reactive({
data: 'anything
});
function changeData(v){
state.data = v
}
return { changeData}
},
</script>
//Child
<template>
<button #click='change('hello')' />
</template>
<script>
setup() {
function change(v){
this.$emit('onchangeData', v)
}
return{change}
},
</script>
I am struggling to change the parents' reactive state from the child's button click. It's saying this.$emit is not a function. I tried many ways like using #onchangeData='changeData()' instead of #onchangeData='changeData', using arrow functions etc. But nothing works. Here, I wrote an example and minimal code to keep it simple. But I hope my problem is clear.
Look at following snippet, this is not the same in composition as in options API, so you need to use emit passed to setup function:
const { reactive } = Vue
const app = Vue.createApp({
setup() {
const state = reactive({
data: 'anything'
});
function changeData(v){
state.data = v
}
return { changeData, state }
},
})
app.component("ChildComp", {
template: `
<div>
<button #click="change('hello')">click</button>
</div>
`,
setup(props, {emit}) {
function change(v){
emit('onchangeData', v)
}
return { change }
},
})
app.mount('#demo')
<script src="https://unpkg.com/vue#3/dist/vue.global.prod.js"></script>
<div id="demo">
<child-comp #onchange-data='changeData'></child-comp>
<p>{{ state.data }}</p>
</div>

Unable to set VueJs Component data values from component prop

For some reason, the value for customer_data.customerReference is never available yet I can see using Chrome debugging tools that the data exists in the prop and is successfully passed from my app down to the component.
Vue.component("mycomponent", {
template: '#my-component-template',
props: ["customer_data"],
data() {
return {
myData: 'This works fine!',
form_data: {
customerRef: this.customer_data.customerReference
}
}
}
});
new Vue({
el: "#app",
data() {
return {
customer: {
customerReference: 007
}
};
}
});
Here is my markup including the template:
<div id="app">
<mycomponent customer_data="customer" />
</div>
<script type="x-template" id="my-component-template">
<div>
<p>{{form_data.customerRef}}</p>
<p>{{myData}}</p>
</div>
</script>
Please see the following JsFiddle with a simplified example:
https://jsfiddle.net/ProNotion/a8c6nqsg/20/
What is that I am missing here or implementing incorrectly?
You should bind it using v-bind: or just :
<div id="app">
<mycomponent :customer_data="customer" />
</div>
https://v2.vuejs.org/v2/guide/components-props.html
You're passing in a string that says 'customer' and not the actual customer object. All you need to do is change customer_data="customer" to v-bind:customer_data="customer"

Vue v-model changes parent data but doesn't change value prop in custom component

someone to help me with this strange issue?
I have the following vue component:
<template lang="pug">
div
p.alert.alert-info {{value}}
button(#click="onChange") Change
</template>
<script>
import Vue from 'vue';
export default {
name: 'z-temp',
props: {
value: {
required: true
}
},
watch: {
value(val) {
console.log(val);
}
},
methods: {
onChange() {
this.$emit('input', Random.id());
}
}
};
</script>
I want to use v-model, but when I use <z-temp v-model="myDataField">, the myDataField changes with success when I click in the Change button, but when I make the inverse and put some value in myDataField, like myDataField: "foo" the custom component gets this.value as undefined instead as foo.
Can anyone help me please?
I am guessing that myDataField is not reactive so the problem is in the parent.
Can you clarify the problem, seems like it is working as it should, ie. the component does not seem to be the problem.
zTemp = Vue.component('ztemp', {
template: '#ztemp',
props: {
value: {
required: true
}
},
watch: {
value(val) {
console.log(val);
}
},
methods: {
onChange() {
this.$emit('input', Math.random());
}
}
});
new Vue({
el: '#app',
components: {
zTemp
},
data: {
myinput: '0.2'
}
});
<script src="https://cdnjs.cloudflare.com/ajax/libs/vue/2.4.4/vue.min.js"></script>
<div id="app">
{{myinput}}<br/>
<input v-model="myinput"/><br/>
<ztemp v-model="myinput"/><br/>
</div>
<script type="text/x-template" id="ztemp">
<div>
<p>{{value}}</p>
<button #click="onChange">Change</button>
</div>
</script>
thanks for helping, but I'm using meteor with vue-meteor, the problem was related to vue-meteor.
I changed the project structure to use separated Vue project in a .client folder and the problem gones. It was not a problema with component, but with vue-meteor package. Anyway, thank you guys.

Vue.js use correct component

I've got a main-component in that main-component I've a sub-component with vue.js 2.0.
The problem is that the sub-component uses the methods in the main-component.
I've made an example:
Vue.component('main-component', {
template: '<p>This is the main component. <sub-component><button #click="test()">If this button is presses: "sub-component" must show up. </button></sub-component></p>',
methods: {
test() {
alert('main-component');
}
}
})
Vue.component('sub-component', {
template: '<p>This is sub-component <slot></slot> </p>',
methods: {
test() {
alert('sub-component');
}
}
})
var app = new Vue({
el: '#app'
})
<script src="https://vuejs.org/js/vue.min.js"></script>
<div id="app">
<main-component></main-component>
</div>
How do I make sure the sub-component uses it's own methods, and in this case give an alert of: 'sub-component' instead of 'main-component' when the button is being pressed?
Use a scoped slot.
Vue.component('main-component', {
template: `
<p>This is the main component.
<sub-component>
<template scope="{test}">
<button #click="test()">If this button is presses: "sub-component" must show up. </button>
</template>
</sub-component>
</p>`,
methods: {
test() {
alert('main-component');
}
}
})
Vue.component('sub-component', {
template: '<p>This is sub-component <slot :test="test"></slot> </p>',
methods: {
test() {
alert('sub-component');
}
}
})
var app = new Vue({
el: '#app'
})
<script src="https://vuejs.org/js/vue.min.js"></script>
<div id="app">
<main-component></main-component>
</div>
Perhaps you can try something like this:
<sub-component ref="sub"><button #click="$refs.sub.test()">...</button></sub-component>

Vue instance inside Vue instance

Sup people!
I got this HTML code here:
// index.html
<div data-init="component-one">
<...>
<div data-init="component-two">
<button #click="doSomething($event)">
</div>
</div>
This basically references a Vue instance inside another Vue instance if I understood everything correctly. The respective JS code is split up in two files and looks like this:
// componentOne.js
new Vue(
el: '[data-init="component-one"]',
data: {...},
methods: {...}
);
// componentTwo.js
new Vue(
el: '[data-init="component-two"]'
data: {...}
methods: {
doSomething: function(event) {...}
}
);
Now, the problem with this is, that doSomething from componentTwo never gets called.
But when I do some inline stuff, like {{ 3 + 3 }}, it gets computed like it should. So Vue knows there is something. And it also removes the #click element on page load.
I tried fiddling around with inline-template as well, but it doesn't really work as I'd expect it to in this situation. And I figured it isn't meant for this case anyway, so I dropped it again.
What would the correct approach be here? And how can I make this work the easiest way possible with how it's set up right now?
The Vue version we use is 2.1.8.
Cheers!
The problem is that you have two vue instances nested to each other.
If the elements are nested, then you should use the same instance or try components
https://jsfiddle.net/p16y2g16/1/
// componentTwo.js
var item = Vue.component('item',({
name:'item',
template:'<button #click="doSomething($event)">{{ message2 }</button>',
data: function(){
return{
message2: 'ddddddddddd!'
}},
methods: {
doSomething: function(event) {alert('s')}
}
}));
var app = new Vue({
el: '[data-init="component-one"]',
data: {
message: 'Hello Vue!'
}
});
<div data-init="component-one">
<button >{{ message }}</button>
<item></item>
</div>
Separate instances work if they are independant of each other.
as follows:
https://jsfiddle.net/p16y2g16/
var app = new Vue({
el: '[data-init="component-one"]',
data: {
message: 'Hello Vue!'
}
});
// componentTwo.js
var ddd = new Vue({
el: '[data-init="component-two"]',
data: {
message: 'ddddddddddd!'
},
methods: {
doSomething: function(event) {alert('s')}
}
});
But when I do some inline stuff, like {{ 3 + 3 }}, it gets computed like it should. So Vue knows there is something.
Because you have parent instance 'componentOne'. It activated Vue for this template. If you need to set another instance inside, you have to separate part of template. Example (it can lag in snippet!) .
Alternative
https://jsfiddle.net/qh8a8ebg/2/
// componentOne.js
new Vue({
el: '[data-init="component-one"]',
data: {
text: 'first'
},
methods: {}
});
// componentTwo.js
new Vue({
el: '[data-init="component-two"]',
data: {
text: 'second'
},
template: `<button #click="doSomething($event)">{{text}}</button>`,
methods: {
doSomething: function(event) {
console.log(event);
}
}
});
<script src="https://vuejs.org/js/vue.min.js"></script>
<div data-init="component-one">
{{text}}
</div>
<div data-init="component-two">
</div>
The button element inside component-two is referenced as a slot in Vue.
The evaluation of the #click directive value happens in the parent component (component-one, which host component-two). Therefor, you need to declare the click handler over there (over component-one).
If you want the handler to be handled inside component-two, you should declare a click directive for the slot element in it's (component-two) template, and pass the handler function, for instance, as a pop.
good luck.
You're doing everything right except you've nested the 2nd Vue instance inside the 1st. Just put it to the side and it will work as expected.
Vue ignores binding more than once to the same element to avoid infinite loops, which is the only reason it doesn't work nested.
Use vue-cli to create a webpack starter app. vue init app --webpack
Then, try to structure your components this way. Read more: https://v2.vuejs.org/v2/guide/components.html#What-are-Components
This is main.js
import Vue from 'vue'
import ComponentOne from './ComponentOne.vue'
import ComponentTwo from './ComponentTwo.vue'
new Vue({
el: '#app',
template: '<App/>',
components: {
ComponentOne,
ComponentTwo
}
})
This is ComponentOne.vue
<template>
<div class="user">
<div v-for="user in users">
<p>Username: {{ user.username }}</p>
</div>
</div>
</template>
<script>
export default {
data () {
return {
users: [
{username: 'Bryan'},
{username: 'Gwen'},
{username: 'Gabriel'}
]
}
}
}
</script>
This is ComponentTwo.vue
<template>
<div class="two">
Hello World
</div>
</template>
<script>
export default {
}
</script>
<div th:if="${msg.replyFloor}">
<div class="msg-lists-item-left">
<span class="msg-left-edit"
th:classappend=" ${msg.unreadCount == 0} ? 'msg-all-read' ">您在</span>
<span th:text="${msg.topic.title}"
class="msg-left-edit-res"
th:classappend=" ${msg.unreadCount == 0} ? 'msg-all-read' ">问题回答</span>
<span th:text="${msg.type.name}"
class="msg-left-edit "
th:classappend=" ${msg.unreadCount == 0} ? 'msg-all-read' ">帖子相关</span>
<span class="msg-left-edit-number" >
产生了<span th:text="${msg.unreadCount} ? : ${msg.unreadCount} + '条新' : ${msg.unreadCount} + '条' "
th:class="${msg.unreadCount} ? : 'number-inner':''">2132条</span>回复
</span>
</div>
<div class="msg-lists-item-right">
<span th:text="${msg.lastShowTime}">2017-8-10</span>
</div>
</div>

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