Binding Vue.js to all instances of an element, without(?) using Components - laravel

Question

Today I'm learning Vue.js, and I have a few ideas of where it might be really useful in a new project that's an off-shoot of an existing, live project.
I like the idea of trying to replace some of my existing functionality with Vue, and I see that Components may be quite handy as quite a lot of functionality is re-used (e.g. Postcode lookups).
Once of the pieces of functionality I've used for an age is for invalid form elements - currently in jQuery when a form input or textarea is blurred I add a class of form__blurred, and that is coupled with some Sass such as:
.form__blurred {
&:not(:focus):invalid {
border-color:$danger;
}
}
This is to avoid styling all required inputs as errors immediately on page load.
I'm totally fine with doing this in jQuery, but I figured maybe it could be done in Vue.
I have an idea of how I might do it with components thanks to the laracasts series, but my form inputs are all rendered by Blade based on data received from Laravel and it doesn't seem like a neat solution to have some of the inputs rendered in Javascript, for a number of reasons (no JS, confusion about where to find input templates, etc).
I figured something like the following simplified example would be handy
<input type="text" class="form__text" v-on:blur="blurred" v-bind:class="{ form__blurred : isBlurred }" />
<script>
var form = new Vue({
el : '.form__input',
data : {
isBlurred : false
},
methods : {
blurred : function() {
this.isBlurred = true;
}
}
});
</script>
That actually works great but, as expected, it seems like using a class selector only selects the first instance, and even if it didn't, I'm guessing changing the properties would apply to all elements, not each one individually.
So the question is - is this possible with pre-rendered HTML, in a way that's smarter than just looping through a selector?
If it is, is there a way to create the Vue on a .form element and apply this function to both .form__input and .form__textarea?
Or, as is probably the case, is this just not a good use-case for Vue (since this is actually a lot more code than the jQuery solution).

Answer 1

Sounds like a great use case for a Custom Directive.
Vue allows you to register your own custom directives. Note that in Vue 2.0, the primary form of code reuse and abstraction is components - however there may be cases where you just need some low-level DOM access on plain elements, and this is where custom directives would still be useful.
<div id="app">
<input type="text" name="myforminput" v-my-directive>
</div>
<script>
Vue.directive('my-directive', {
bind: function (el) {
el.onblur = function () {
el.classList.add('form__blurred');
}
}
});
var app = new Vue({
el: '#app'
});
</script>
You can also add the directive locally to a parent component, if it makes sense for your application.