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/[email protected]/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/[email protected]/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>