Vuejs event modifiers

Question

This is from the docs :

@click.prevent.self will prevent all clicks while @click.self.prevent will only prevent clicks on the element itself.

I tried making a fiddle to actually prevent all clicks but am unsuccessful. Can someone elaborate what this line in the docs actually mean?

Fiddle:

 var app = new Vue({ el: '#appp', methods: { logger(arg) { console.log(arg); } } });

 <script src="https://cdn.jsdelivr.net/npm/vue@2.5.13/dist/vue.js"></script> <div id="appp"> <div @click.prevent.self="logger('1')"> 1 <br> <div @click.prevent.self="logger('2')"> ..2 <br> <div @click.prevent.self="logger('3')"> ....3 </div> </div> </div> </div>

Answer 1

One of the best ways to see how .prevent and .self interact is looking at the output of the Vue compiler :

.prevent.self :

on: {
    "click": function($event){
        $event.preventDefault();
        if($event.target !== $event.currentTarget)
            return null;
        logger($event)
    }
}

.self.prevent

on: {
    "click": function($event){
        if($event.target !== $event.currentTarget)
            return null;
        $event.preventDefault();
        logger($event)
    }
}

The key difference between those 2 code blocks is inside the fact that the order of the operations matters, a .prevent.self will prevent events coming from its children, but doesn't run any code, but a .self.prevent will only cancel events directly created by itself, and ignores child requests completely.

Demo:

 var app = new Vue({ el: '#appp', data: {log:[]}, methods: { logger(arg) { this.log.push(arg); } } });

 <script src="https://cdn.jsdelivr.net/npm/vue@2.5.13/dist/vue.js"></script> <div id="appp" style="display: flex; flex-direction: row;"> <form @submit.prevent="logger('form')" style="width: 50%;"> <button> <p @click.prevent.self="logger('prevent.self')"> prevent.self <span>(child)</span> </p> <p @click.self.prevent="logger('self.prevent')"> self.prevent <span>(child)</span> </p> <p @click.prevent="logger('prevent')"> prevent <span>(child)</span> </p> <p @click.self="logger('self')"> self <span>(child)</span> </p> <p @click="logger('none')"> none <span>(child)</span> </p> </button> </form> <pre style="width: 50%;">{{log}}</pre> </div> </div>