VueJS 2 update contenteditable in component from parent method - vue.js

Question

I have editable element updated by component method, but i have also json import and i want to update element my parent method. I can update model, but editable element doesn´t bind it. If i insert content to component template, it will bind updated model, but then i can´t really edit it.
Here´s my example: https://jsfiddle.net/kuwf9auc/1/
Vue.component('editable', {
template: '<div contenteditable="true" #input="update"></div>', /* if i insert {{content}} into this div, it wil update, but editing behave weird */
props: ['content'],
mounted: function () {
this.$el.innerText = this.content;
},
methods: {
update: function (event) {
console.log(this.content);
console.log(event.target.innerText);
this.$emit('update', event.target.innerText);
}
}
})
var app = new Vue({
el: '#myapp',
data: {
herobanner: {
headline: 'I can be edited by typing, but not updated with JSON upload.'
}
},
methods: {
uploadJSON: function (event) {
var input = event.target;
input.src = URL.createObjectURL(event.target.files[0]);
var data = input.src;
$.get(data, function(data) {
importdata = $.parseJSON(data);
this.$data.herobanner = importdata.herobanner;
}.bind(this));
}
}
})
<script src="https://cdnjs.cloudflare.com/ajax/libs/vue/2.4.2/vue.min.js"></script>
<script src="https://ajax.googleapis.com/ajax/libs/jquery/2.1.1/jquery.min.js"></script>
<main id="myapp" class="container-fluid">
<input type="file" id="file" name="file" #change="uploadJSON" style="display: none; width: 1px; height: 1px"/>
<a href="" onclick="document.getElementById('file').click(); return false" title="Import settings from JSON file">
upload JSON
</a>
<h1>
<editable :content="herobanner.headline" #update="herobanner.headline = $event"></editable>
</h1>
Real value of model:
<br>
<h2>{{herobanner.headline}}</h2>
</main>

Answer 1

Working example:
Vue.component('editable', {
template: `
<div contenteditable="true" #blur="emitChange">
{{ content }}
</div>
`,
props: ['content'],
methods: {
emitChange (ev) {
this.$emit('update', ev.target.textContent)
}
}
})
new Vue({
el: '#app',
data: {
herobanner: {
headline: 'Parent is updated on blur event, so click outside this text to update it.'
}
},
methods: {
async loadJson () {
var response = await fetch('https://swapi.co/api/people/1')
var hero = await response.json()
this.herobanner.headline = hero.name
},
updateHeadline (content) {
this.herobanner.headline = content
}
}
})
<main id="app">
<button #click="loadJson">Load JSON data</button>
<h1>
<editable
:content="herobanner.headline"
v-on:update="updateHeadline"
>
</editable>
</h1>
<h2>{{herobanner.headline}}</h2>
</main>
<script src="https://unpkg.com/vue#2.5.3/dist/vue.min.js"></script>