I try to bind child input value to the parent value. I pass value searchText from a Parent component to a Child component as prop :valueProp. There I assign it to property value: this.valueProp and bind input:
<input type="text" :value="value" #input="$emit('changeInput', $event.target.value)" />
The problem is that input doesn't work with such setup, nothing displays in input, but parent searchText and valueProp in child update only with the last typed letter; value in child doesn't update at all, though it is set to equal to searchText.
If I remove :value="value" in input, all will work fine, but value in child doesn't get updated along with parent's searchText.
I know that in such cases it's better to use v-model, but I want to figure out the reason behind such behavior in that case.
I can't understand why it works in such way and value in child component doesn't update with parent's searchText. Can you please explain why it behaves in that way?
Link to Sanbox: Sandbox
Parent:
<template>
<div>
<Child :valueProp="searchText" #changeInput="changeInput" />
<p>parent {{ searchText }}</p>
</div>
</template>
<script>
import Child from "./Child.vue";
export default {
name: "Parent",
components: { Child },
data() {
return {
searchText: "",
};
},
methods: {
changeInput(data) {
console.log(data);
this.searchText = data;
},
},
};
</script>
Child:
<template>
<div>
<input type="text" :value="value" #input="$emit('changeInput', $event.target.value)" />
<p>value: {{ value }}</p>
<p>child: {{ valueProp }}</p>
</div>
</template>
<script>
export default {
emits: ["changeInput"],
data() {
return {
value: this.valueProp,
};
},
props: {
valueProp: {
type: String,
required: true,
},
},
};
</script>
You set the value in your Child component only once by instantiating.
In the data() you set the initial value of your data properties:
data() {
return {
value: this.valueProp,
};
},
Since you don't use v-model, the value will never be updated.
You have the following options to fix it:
The best one is to use v-model with value in the Child.vue
<input
type="text"
v-model="value"
update value using watcher
watch: {
valueProp(newValue) {
this.value = newValue;
}
},
use a computed property for value instead of data property
computed: {
value() {return this.valueProp;}
}
Respect for creating the sandbox!
You are overwriting the local value every time the value changes
data() {
return {
value: this.valueProp, // Don't do this
};
},
Bind directly to the prop:
<input ... :value="valueProp" ... />
Related
I need to execute a v-for, however I do not know how to add a v-model for each different component inside of v-for;
<template>
<ProfilePasswordField
v-for="(item, index) in profilePasswordItems"
:key="index"
:profilePasswordItem="item"
v-model="???"
>
</template>
This v-for will always be three items and I want to name the v-model's as: ['passaword', 'newPassword', confirmNewPassword']
How can I add those names dinamically for the v-model inside v-for?
I tried to do a list inside data() but it did not work. Something like that:
data (){
return{
listPassword: ['passaword', 'newPassword', 'confirmNewPassword']
}
},
methods: {
method1 () {
console.log(this.passaword)
console.log(this.newPassword)
console.log(this.confirmNewPassword)
}
}
The v-model directives cannot update the iteration variable itself therefore we should not use a linear array item in for-loop as the v-model variable.
There is another method you can try like this-
In the parent component-
<template>
<div>
<ProfilePasswordField
v-for="(item, index) in listPassword"
:key="index"
:profilePasswordItem="item"
v-model="item.model"
/>
<button #click="method1()">Click to see changes</button>
</div>
</template>
<script>
export default {
name: "SomeParentComponent",
data() {
return {
listPassword: [
{ model: "passaword" },
{ model: "newPassword" },
{ model: "confirmNewPassword" },
],
};
},
methods: {
method1() {
this.listPassword.forEach((item) => {
console.log(item.model);
});
},
},
}
</script>
And in your ProfilePasswordField you can emit the input event to listen to the respected changes in v-model binding. For example, the ProfilePasswordField component could be like this-
<template>
<v-text-field :value="value" #input="$emit('input', $event)"/>
</template>
<script>
export default {
name: "ProfilePasswordField",
props: {
value: {
required: true
}
}
</script>
In the parent component's console, you should see the changes made by the child component.
Vcode is in a child component.
data() {
return {
vcode: null,
};
},
I need to access this value in a parent component method.
verifyCode() {
const code = this.vcode
}
Attempting this returns undefined. How do I access this value?
Update
I tried the suggestions and I still get an undefined value
Input field on child component
<input
class="form-control mt-5"
v-model.trim="vcode"
:class="{'is-invalid' : $v.vcode.$error }"
#input="$v.vcode.$touch(), vcodenum = $event.target.value"
placeholder="Enter your 6 digit code"
/>
On the parent component I added the following where it references the child component
<step2 ref="step2" #on-validate="mergePartialModels" v-on:vcodenum="vcode = $event"></step2>
My method in the parent component
verifyCode() {
const code = this.vcode
console.log(code)
}
I still get undefined.
I also tried this:
Child component
<input
class="form-control mt-5"
v-model.trim="vcode"
:class="{ 'is-invalid': $v.vcode.$error }"
#input="$v.vcode.$touch(), onInput"
placeholder="Enter your 6 digit code"
/>
Props
props: {
value: {
type: [String, Number, Boolean],
default: "",
},
},
method
onInput(e) {
this.$emit('on-input', e.target.value)
},
Parent
<step2 ref="step2" #on-validate="mergePartialModels" :value="vcode" #on-input="handleInput"></step2>
data() {
return {
vcode: null
};
},
method
handleInput(value) {
this.vcode = value
console.log(this.vcode)
},
The value ends up outputting null.
If I use the v-bind I get this error:
:value="value" conflicts with v-model on the same element because the latter already expands to a value binding internally
You can listen to the child's input event and send the value to the parent.
// InputComponent.vue
<input :value="value" #input="onInput" />
....
props: {
value: {
type: [String, Number, Boolean] // Add any custom types,
default: ''
}
},
methods: {
onInput(e) {
this.$emit('on-input', e.target.value)
}
}
// Parent.vue
<InputComponent :value="vCode" #on-input="handleInput" />
....
data() {
return {
vcode: null
}
},
methods: {
handleInput(value) {
this.vode = value
}
}
I have a question why not this component, not re-rendering after changing value so what I'm trying to do is a dynamic filter like amazon using the only checkboxes so let's see
I have 4 components [ App.vue, test-filter.vue, filtersInputs.vue, checkboxs.vue]
Here is code sandbox for my example please check the console you will see the value changing https://codesandbox.io/s/thirsty-varahamihira-nhgex?file=/src/test-filter/index.vue
the first component is App.vue;
<template>
<div id="app">
<h1>Filter</h1>
{{ test }}
<test-filter :filters="filters" :value="test"></test-filter>
</div>
</template>
<script>
import testFilter from "./test-filter";
import filters from "./filters";
export default {
name: "App",
components: {
testFilter,
},
data() {
return {
filters: filters,
test: {},
};
},
};
</script>
so App.vue that holds the filter component and the test value that I want to display and the filters data is dummy data that hold array of objects.
in my test-filter component, I loop throw the filters props and the filterInputs component output the input I want in this case the checkboxes.
test-filter.vue
<template>
<div class="test-filter">
<div
class="test-filter__filter-holder"
v-for="filter in filters"
:key="filter.id"
>
<p class="test-filter__title">
{{ filter.title }}
</p>
<filter-inputs
:value="value"
:filterType="filter.filter_type"
:options="filter.options"
#checkboxChanged="checkboxChanged"
></filter-inputs>
</div>
</div>
<template>
<script>
import filterInputs from "./filterInputs";
export default {
name: "test-filter",
components: {
filterInputs,
},
props:{
filters: {
type: Array,
default: () => [],
},
value: {
type: Array,
default: () => ({}),
},
},
methods:{
checkboxChanged(value){
// Check if there is a array in checkbox key if not asssign an new array.
if (!this.value.checkbox) {
this.value.checkbox = [];
}
this.value.checkbox.push(value)
}
};
</script>
so I need to understand why changing the props value also change to the parent component and in this case the App.vue and I tried to emit the value to the App.vue also the component didn't re-render but if I check the vue dev tool I see the value changed but not in the DOM in {{ test }}.
so I will not be boring you with more code the filterInputs.vue holds child component called checkboxes and from that, I emit the value of selected checkbox from the checkboxes.vue to the filterInputs.vue to the test-filter.vue and every component has the value as props and that it if you want to take a look the rest of components I will be glad if you Did.
filterInpust.vue
<template>
<div>
<check-box
v-if="filterType == checkboxName"
:options="options"
:value="value"
#checkboxChanged="checkboxChanged"
></check-box>
</div>
</template>
<script>
export default {
props: {
value: {
type: Object,
default: () => ({}),
},
options: {
type: Array,
default: () => [],
},
methods: {
checkboxChanged(value) {
this.$emit("checkboxChanged", value);
},
},
}
</script>
checkboxes.vue
<template>
<div>
<div
v-for="checkbox in options"
:key="checkbox.id"
>
<input
type="checkbox"
:id="`id_${_uid}${checkbox.id}`"
#change="checkboxChange"
:value="checkbox"
/>
<label
:for="`id_${_uid}${checkbox.id}`"
>
{{ checkbox.title }}
</label>
</div>
</div>
<template>
<script>
export default {
props: {
value: {
type: Object,
default: () => ({}),
},
options: {
type: Array,
default: () => [],
},
}
methods: {
checkboxChange(event) {
this.$emit("checkboxChanged", event.target.value);
},
},
};
</script>
I found the solution As I said in the comments the problem was that I'm not using v-model in my checkbox input Vue is a really great framework the problem wasn't in the depth, I test the v-model in my checkbox input and I found it re-render the component after I select any checkbox so I search more and found this article and inside of it explained how we can implement v-model in the custom component so that was the solution to my problem and also I update my codeSandbox Example if you want to check it out.
Big Thaks to all who supported me to found the solution: sarkiroka, Jakub A Suplick
Here's sample of my child component
HTML:
<div v-for="(input, index) in form.inputs" :key="index">
<div>
<input :name"input.name" :type="input.type" />
</div>
</div>
JavaScript (Vue):
<script>
export default {
name: "child",
props: ['parentForm'],
data() {
return {
form: {
inputs: [
{
name: 'name',
type: 'text'
],
[...]
}
}
}
And sample of root component
HTML:
<child :parentsForm="form"></child>
JavaScript (Vue):
<script>
import child from "./child";
export default {
name: "root",
components: { child },
data() {
return {
form: {
data: {
name: null,
email: null,
...
}
}
}
The question is, how do I achieve combining root + v-for?
Example I want to using child component this way
<input :name"input.name" :type="input.type" v-model="parentForm.data . input.name" />
Since parentForm.data will bind form:data:{ and this will be the variable get from input.name }
Output in v-model should be bind form.data.name or form.data.email on root component
Thank you
You can use it as per follow,
<input :name="input.name" :type="input.type" v-model="parentForm.data[input.name]" />
This will bind parentForm.data.name for input.name = 'name' to v-model.
If I understood you correctly, you want to update parent data from your child component. If yes then you have two options.
In you child component use $parent.form.data to bind.
Or you can pass it down as prop assign it to a data property in child. Bind this new data property in your child and emit it whenever any changes are made. Receive this emit in your parent and update the parent property respectively (Recommended)
The problem: Whenever I increment the input field provided by the child component, the value doesn't set back to zero. It assumes the value of the previous instance.
Note: The increment is implemented in parent component method
Child component
<input type="number" placeholder="Amount" :value="value" #input="$emit('input',$event.target.value/>
<script>
export default {
props: ["value"],
data() {
return {};
}
};
</script>
Parent Component
<template>
<div>
<form-input v-for="n in count" :key="n" v-model="expense"> </form-input>
<button #click="addInputs">Add Expense</button>
<button #click="deleteInputs">Delete</button>
</div>
</template>
export default {
components: {
"form-input": formInput
},
name: "form",
data() {
return {
count: 0,
earnings: "",
expense: ""
};
},
methods: {
addInputs: function() {
this.count++;
},
deleteInputs: function() {
this.count--;
}
}
};
</script>
Please feel free to ask any questions if there any more needed information
Why are you passing a value prop from the parent anyway? Shouldn't the value of the child be self-controlled?
Try removing the binding of value.
<input type="number" placeholder="Amount" #input="$emit('input',$event.target.value/>`