How can we add .trim modifier with v-model conditionally?
Creating a global input field for the entire application, some fields need to be trim others not. Making an input for this (isTrim ) in the component.
<input v-model.trim="msg">
Can we add conditionally above trim with the component input?
I dont think you can. I can however suggest a convenient computed property:
<input v-model="valueThatNeedsTrim" />
data() {
return {
valueFromData: "",
}
},
computed() {
valueThatNeedsTrim: {
get() {
return this.valueFromData
},
set(value) {
this.valueFromData = value.trim()
}
}
}
Related
I have a Vue componenet for my input field. I have added some validation that makes sure only numbers are added. I added this on the oninput.
I'd like to move this to a method so I can add more checks (eg. if Type !== number)
This works well, but with the validation inline:
<input
v-bind="$attrs"
v-on="{
...$listeners,
input: event => $emit('input', event.target.value)
}"
oninput="this.value = Math.abs(this.value)"
/>
This is how I would like it (but current the validation is not working):
<input
v-bind="$attrs"
v-on="{
...$listeners,
input: event => handleInput(event.target.value)
}"
/>
methods: {
handleInput(value) {
console.log(value);
// 1st emit
this.$emit("input", value);
// 2nd Validate -- Not working...
this.value = Math.abs(this.value);
}
}
Any ideas on how I get this.value = Math.abs(this.value); to feed back into the input?
UPDATE
Thanks to a helpful comment I made some progress. The below code works for the first character but not for ongoing characters.
If numbers are typed, then validation passes true and input emitted.
If 1 character (eg. a) is typed then we emit the number 0. If a second character is inputted then the char is emitted (eg. press b and now the input is 0b)
I can see the this.$emit("input", 0) is triggered, so not sure why char emitted.
methods: {
validateInput(value) {
// if it type isnt set as a number then leave
if (this.type != "number") {
return true;
}
// check if value a number
if (Math.abs(value)) {
return true;
}
return false;
},
handleInput(value) {
if (this.validateInput(value)) {
this.$emit("input", value);
} else {
this.$emit("input", 0);
}
}
}
If you want to check a value before emitting the input event, you could do it like this:
methods: {
validateInput(value) {
if (typeof value !== 'number') { return false; } // check if it's not a string
if (value !== Math.abs(value)) { return false; } // check if value is positive
return true
}
handleInput(value) {
if (this.validateInput(value)) { this.$emit("input", value); }
this.$emit("input") // if value is not a valid input, you may want to do nothing, or emit merely that the event happened.
}
}
A better way of doing a custom input would be to use the value prop of an input, and bind it to a dynamic property in your component, for example by using v-model="value". Fun fact: v-model has a modifier v-model.number which would do exactly what you need.
The only caveat is that you can't directly modify props, so you'd need to use a computed property as a way to automatically handle the 'getting and setting' of your form's value.
// CustomInput.vue
<template>
<input v-bind="$attrs" v-on="$listeners" v-model.number="localValue" />
</template>
<script>
export default {
props: {
value: {
type: Number,
required: true,
}
}
computed: {
localValue: {
get() { return this.value; }
set(newVal) { this.$emit('input', newVal); }
}
}
}
</script>
You don't need to make a custom component for this case. You could simply use v-model.number in the parent and it would work. Once your inputs get more complex, you want to modify the set method a bit to set(newVal) { if (this.validateInput(newVal)) {this.$emit('input', newVal);} }, defining your own 'validateInput' method.
If you find you're writing a lot of different validations for different use cases, look into libraries like Vuelidate and VeeValidate
I'm creating a form using vue.js and I need to create inputs in vue that is always capitalized. I know I could use the css property
text-transform: uppercase;
and then transform the data before sending using
data.someData.toUpperCase()
But I wonder if there is a more intelligent way of doing that in vue.js. In react we can create controlled inputs and easily do it. Is there anything like that in Vue.js?
I managed to do it using computed fields, however, I would have to create computed getter and setter for each input in the form. Is there a better way of doing it?
You could create a custom directive.
Vue.directive( 'touppercase', {
update (el) {
el.value = el.value.toUpperCase()
},
})
And then use it where you need. For example:
<input type="text" v-model="modelfield" v-touppercase>
Since you don't have a lot of code to run, you should manually bind events to your textfield and then handle the uppercasing there.
Handling events from a text field can be done by adding an input event handler on them, and then updating the initial state again.
<input :value="text" #input="updateText($event.target.value)"/>
export default {
data() {
return {
text: '',
}
},
methods: {
updateText(newValue) {
this.value = newValue.toUpperCase();
},
}
}
You can also do it inline in a template, but this might make it harder to read depending on your code style preferences
<input :value="text" #input="text = $event.target.value.toUpperCase()"/>
This directive works fine with v-model (last character is in upper case too):
Vue.directive('uppercase', {
update(el) {
const sourceValue = el.value;
const newValue = sourceValue.toUpperCase();
if (sourceValue !== newValue) {
el.value = newValue;
el.dispatchEvent(new Event('input', { bubbles: true }));
}
},
});
Usage:
<input type="text" v-model="myField" v-uppercase />
You can do this:
<input :value="theValue" #input="theValue = theValue.toUpperCase()"/>
as a fix for asologor's answer you should reach input element to change it at vuetify
Vue.directive("uppercase", {
update(el) {
const sourceValue = el.getElementsByTagName("input")[0].value
const newValue = sourceValue.toUpperCase()
if (sourceValue !== newValue) {
el.getElementsByTagName("input")[0].value = newValue
el = el.getElementsByTagName("input")[0]
el.dispatchEvent(new Event("input", { bubbles: true }))
}
}
})
and usage is
<v-text-field
type="text"
outlined
placeholder="placeholder"
v-model="name"
prepend-inner-icon="edit"
v-uppercase
/>
this is defnetely working
I've got form with dynamic number of input fields and i need to transliterate data, passed to this fields in 'live'. I wrote custom directive which do all job, but there is an a error -> it converts all chars except last one (should be привет->privet, while привет->priveт). This is my source code
directives: {
transliterate: {
update(element, binding) {
element.value = tr(element.value)
}
}
}
This is PUG (Jade)
input(v-model='requestHotels.travellers[index].first_name', v-transliterate='true')
tr - just function, which transliterate from ru to en
I knew why this happening, but i can't solve it by myself. Any ideas?
1) Consider using computed property instead of directive. Personally, I don't like directives because they can add alot of useless complexity to your code. But there are some complex cases where they can be really useful. But this one is not one of them.
export default {
data: () => ({
tranliteratedValue: ""
}),
computed: {
vModelValue: {
get() {
return this.tranliteratedValue;
},
set(value) {
this.tranliteratedValue = transl.transform(value);
}
}
}
};
Full example: https://codesandbox.io/s/039vvo13yv?module=%2Fsrc%2Fcomponents%2FComputedProperty.vue
2) You can use filter and transliterate during render
filters: {
transliterate(value) {
return transl.transform(value);
}
}
Then in your template:
<p>{{ value | transliterate }}</p>
Full example: https://codesandbox.io/s/039vvo13yv?module=%2Fsrc%2Fcomponents%2FFilter.vue
3) Transparent wrapper technique (using custom component)
The idea behind transparent wrapper is that you should create custom component that behave as build-in input (and accepts the same arguments) but you can intercept events and change behaviour as you'd like. In your example - tranliterate input text.
<textarea
v-bind="$attrs"
:value="value"
v-on="listeners"
/>
computed: {
listeners() {
return {
...this.$listeners,
input: event => {
const value = transl.transform(event.target.value + "");
this.$emit("input", value);
}
};
}
}
Full example: https://codesandbox.io/s/039vvo13yv?module=%2Fsrc%2Fcomponents%2Finc%2FTransliteratedInput.vue
Read more about Transparent wrapper technique here https://github.com/chrisvfritz/7-secret-patterns/blob/master/slides-2018-03-03-spotlight-export.pdf
You can check all 3 working approaches here https://codesandbox.io/s/039vvo13yv
I have an input attribute that I want to have text from a source and is two-way binded
// messages.html
<input type="textarea" v-model="newMessage">
// messages.js
data () {
newMessage: ''
},
props: {
message: {
type: Object,
required: true,
default () {
return {};
}
}
// the message object has keys of id, text, and hashtag
I would like the initial value of input to be message.text. Would it be appropriate to do something like newMessage: this.message.text?
EDIT
I tried adding :value="message.text" in input but that didn't really show anything
Yes, you can reference the props in the data function.
data(){
return {
newMessage: this.message.text
}
}
How do I access $refs inside computed? It's always undefined the first time the computed property is run.
Going to answer my own question here, I couldn't find a satisfactory answer anywhere else. Sometimes you just need access to a dom element to make some calculations. Hopefully this is helpful to others.
I had to trick Vue to update the computed property once the component was mounted.
Vue.component('my-component', {
data(){
return {
isMounted: false
}
},
computed:{
property(){
if(!this.isMounted)
return;
// this.$refs is available
}
},
mounted(){
this.isMounted = true;
}
})
I think it is important to quote the Vue js guide:
$refs are only populated after the component has been rendered, and they are not reactive. It is only meant as an escape hatch for direct child manipulation - you should avoid accessing $refs from within templates or computed properties.
It is therefore not something you're supposed to do, although you can always hack your way around it.
If you need the $refs after an v-if you could use the updated() hook.
<div v-if="myProp"></div>
updated() {
if (!this.myProp) return;
/// this.$refs is available
},
I just came with this same problem and realized that this is the type of situation that computed properties will not work.
According to the current documentation (https://v2.vuejs.org/v2/guide/computed.html):
"[...]Instead of a computed property, we can define the same function as a method. For the end result, the two approaches are indeed exactly the same. However, the difference is that computed properties are cached based on their reactive dependencies. A computed property will only re-evaluate when some of its reactive dependencies have changed"
So, what (probably) happen in these situations is that finishing the mounted lifecycle of the component and setting the refs doesn't count as a reactive change on the dependencies of the computed property.
For example, in my case I have a button that need to be disabled when there is no selected row in my ref table.
So, this code will not work:
<button :disabled="!anySelected">Test</button>
computed: {
anySelected () {
if (!this.$refs.table) return false
return this.$refs.table.selected.length > 0
}
}
What you can do is replace the computed property to a method, and that should work properly:
<button :disabled="!anySelected()">Test</button>
methods: {
anySelected () {
if (!this.$refs.table) return false
return this.$refs.table.selected.length > 0
}
}
For others users like me that need just pass some data to prop, I used data instead of computed
Vue.component('my-component', {
data(){
return {
myProp: null
}
},
mounted(){
this.myProp= 'hello'
//$refs is available
// this.myProp is reactive, bind will work to property
}
})
Use property binding if you want. :disabled prop is reactive in this case
<button :disabled="$refs.email ? $refs.email.$v.$invalid : true">Login</button>
But to check two fields i found no other way as dummy method:
<button :disabled="$refs.password ? checkIsValid($refs.email.$v.$invalid, $refs.password.$v.$invalid) : true">
{{data.submitButton.value}}
</button>
methods: {
checkIsValid(email, password) {
return email || password;
}
}
I was in a similar situation and I fixed it with:
data: () => {
return {
foo: null,
}, // data
And then you watch the variable:
watch: {
foo: function() {
if(this.$refs)
this.myVideo = this.$refs.webcam.$el;
return null;
},
} // watch
Notice the if that evaluates the existence of this.$refs and when it changes you get your data.
What I did is to store the references into a data property. Then, I populate this data attribute in mounted event.
data() {
return {
childComps: [] // reference to child comps
}
},
methods: {
// method to populate the data array
getChildComponent() {
var listComps = [];
if (this.$refs && this.$refs.childComps) {
this.$refs.childComps.forEach(comp => {
listComps.push(comp);
});
}
return this.childComps = listComps;
}
},
mounted() {
// Populates only when it is mounted
this.getChildComponent();
},
computed: {
propBasedOnComps() {
var total = 0;
// reference not to $refs but to data childComps array
this.childComps.forEach(comp => {
total += comp.compPropOrMethod;
});
return total;
}
}
Another approach is to avoid $refs completely and just subscribe to events from the child component.
It requires an explicit setter in the child component, but it is reactive and not dependent on mount timing.
Parent component:
<script>
{
data() {
return {
childFoo: null,
}
}
}
</script>
<template>
<div>
<Child #foo="childFoo = $event" />
<!-- reacts to the child foo property -->
{{ childFoo }}
</div>
</template>
Child component:
{
data() {
const data = {
foo: null,
}
this.$emit('foo', data)
return data
},
emits: ['foo'],
methods: {
setFoo(foo) {
this.foo = foo
this.$emit('foo', foo)
}
}
}
<!-- template that calls setFoo e.g. on click -->