Vue $refs and kebab case - vue.js

In vue 1 it was possible to do this:
<app v-ref:test-app></app>
and then reference it like so:
vm.$refs.testApp;
however in vue 2 the syntax for the ref has changed to:
<app ref="test-app"></app>
but this no longer can be referenced by
vm.$refs.testApp
instead it only works if:
<app ref="testApp"></app>
which in standard DOM stuff isn't allowed. Is it a bug? can kebab case no longer be used?

Since the syntax has been changed from that of a namespaced element attribute (i.e., v-ref:foo-bar) to a normal key-value-pair attribute (i.e., ref="fooBar"), the implicit kebab-case-to-camel-case conversion is no longer applicable because the reference name is a plain string and is not constrained by having to conform to the requisite lowercase-kebab-case HTML syntax.
In other words, you can identify a ref with any string, so it wouldn't make sense for Vue to manipulate it. Have a look at this CodePen for an example in action of what I mean.
But, basically, a plain string ref value means you can define a reference like this:
<div id="app" ref="test ** app!"></div>
and reference it from Vue like this:
this.$refs['test ** app!']
In short, no, it's not a bug but no, automatic kebab-case conversion no longer takes place.

Related

Expects an Object or Array value in Vue [ Warn ]

I've been running into a warning that I want to hide/fix. I read you can hide warnings using Vue.config.ignoredElements, and have added the code below in my main.js file:
Vue.config.ignoredElements = [
'slot v-bind without argument expects an Object',
'Expected Object, got Array',
'v-bind without argument expects an Object or Array value'
]
Is there a specific option I need to add? or a better way to fix this problem?
This issue might be related: https://github.com/vuejs/vue/issues/6677
I think you've misunderstood. ignoredElements solves a very specific problem.
Typically when Vue is rendering it comes across 3 types of element:
HTML elements, such as <div>.
Special Vue elements, such as <template> or <slot>.
Components, such as <v-select>.
Vue has a list of HTML elements hard-coded so that it can identify the first group. See:
https://github.com/vuejs/vue/blob/399b53661b167e678e1c740ce788ff6699096734/src/platforms/web/util/element.js#L11
If it comes across an element with a name it doesn't recognise it will log an error. Most of the time that's fine but occasionally you might need Vue to treat an unknown element just like a plain HTML element. That can be achieved by adding it to ignoredElements. See https://v2.vuejs.org/v2/api/#ignoredElements for more details.
It is not used to suppress warning messages more generally.
You mentioned three messages:
slot v-bind without argument expects an Object
Expected Object, got Array
v-bind without argument expects an Object or Array value
In all cases these mean that there's a bug in your code. You shouldn't be trying to suppress these warnings, you should be fixing the bugs.

Vue/vuetify v-switch: what is input-value?

Can someone explain to me exactly what the input-value attribute does on the v-switch component?
I think it has something to due with using the component with vuex, when you cannot use v-model directly.
It seems to be working for me, but I don't understand it exactly.
You can see the attribute here: https://vuetifyjs.com/en/components/selection-controls#api
Where it is described as: "The v-model bound value".
(I originally found the attribute in an example somehere.)
input-value behaves like a default value attribute that you would expect in other components.
Normally v-model is syntax sugar for :value="value" :input="$emit('input', $event.target.value)", but we can change it.
from selectable.js:
model: {
prop: 'inputValue',
event: 'change'
},
So the above lines (see vue docs) make your v-model bind to input-value instead of value likely because some components i.e. checkbox (which v-switch uses) have value attribute reserved for something else.
So value attribute is then used to set the value which will be represented when the component is checked.
And in v-switch case v-model is syntax sugar for something like :input-value="value" #change="value = $event"
Codepen

Vue official website of a confused

Why this "value" can not be written as "pricevalue" or other, otherwise input will not convert non-numeric values
In the props element, you are defining the properties your component will attach to. You can call them whatever you want. You need to be clear about a couple of things...
You define the name here in camelCase, but when you call the component in the parent markup, use kebab-case.
methods only run when they are called. If you put your formatting on the downstream side (receiving a value and displaying it), everything will be reactive and all your values should display correctly. It will all just work whenever the source value changes. So do your formatting in a computed, like this...
js
computed: {
formattedPriceValue(){
return Number.parseFloat(this.priceValue).toFixed(2)
}
}
You can also just do it inline...
markup
<input type="number" :value="Number.parseFloat(priceValue).toFixed(2)">
The value you want to emit is probably the unformatted output of Number.parseFloat #change="$emit('price-changed', Number.parseFloat(event.target.value))"
Then, you will live longer if you do your number formatting with the Number functions provided.
Also, why don't you use the new template (multi-line) strings, delimited by a backtick `. They're much cleaner than the line continuation character you're using.
ps. I love seeing the chinese (?) comments in the code. I've copied and pasted them into my code. I hope there's no swearing. Unicode rocks.

Difference between v-bind and {{}}?

I have an input field with the value field being passed a string stored in Vuex.
The input fields changes are debounced and the new string synced to Vuex.
When bound like this :value="vuexState.myString, when typing, the cursor jumps to the end of the line.
When bound like this value={{vuexState.myString}}, the cursor stays where it is.
According to the guide: http://vuejs.org/guide/syntax.html#Arguments
These two should be the same, with the {{ }} style being internally converted to :bind. Could this be a bug?
My theory is that the cursor jumping occurs because the vuex state change re-renders the input and that the {{ }} style is interpolated only once while the binding syntax re-renders the input every change.
I am currently using value={{vuexState.myString}} but I'd like to know what is happening or if there is a better way to do this.
It's in the documentation about Interpolation and has been deprecated (see. Migration guit from 1.x)
Deprecated
This is the old way
<div class="btn btn-primary hint--top {{class}}"></div>
Solution
Use Javascript expression instead:
<div v-bind:class="'btn btn-success hint--top '+ class "></div>
Take a look at the console, it seems like it has been deprecated in favour of the colon syntax or v-bind:
vue.js:2237 [Vue warn]: foo="{{foo}}": Interpolation inside attributes has been deprecated. Use v-bind or the colon shorthand instead.
v-text:'something' === {{something}}

Serialize C# object using JSON.NET for Dojo data-dojo-props

Dojo's dijit html5 tags use an attribte name data-dojo-props. The value is basically a JSON string without quotes around the property names and without the outermost braces.
It looks something like this.
data-dojo-props="prop1:'xyz', prop2:true, prop3: { subprop1: 1, subprop2: 'abc'}"
I'm using C# to write this out from a C# object using JSON.NET and passing in the object pointer. I found settings to leave out the property name quotes, but I can't figure out a graceful way to remove the outside braces.
For now, I'll run the string through a regex to remove them, but was wondering if someone new a better way.
I serialize each top level property separately and make it a global javascript variable. I then reference that variable in data-dojo-props. I admit it's not that elegant.
My concern with your approach above, is if the value of subprop2 contains a quote, you will get a parser error.
<script type="text/javascript">
menuData = {THE SERIALIZED JSON GOES HERE};
</script>
<div data-dojo-type="SomeWidget" data-dojo-props="menuData: menuData"></div>