vue.js – get new data information - vue.js

Question

I'm building a chrome extension using vue.js. In one of my vue components I get tab informations of the current tab and wanna display this information in my template. This is my code:
<template>
<div>
<p>{{ tab.url }}</p>
</div>
</template>
<script>
export default {
data() {
return {
tab: {},
};
},
created: function() {
chrome.tabs.query({ active: true, windowId: chrome.windows.WINDOW_ID_CURRENT }, function(tabs) {
this.tab = tabs[0];
});
},
};
</script>
The Problem is, that the template gets the data before it's filled through the function. What is the best solution for this problem, when the tab data doesn't change after it is set once.
Do I have to use the watched property, although the data is only changed once?
// EDITED:
I've implemented the solution, but it still doesn't work. Here is my code:
<template>
<div>
<div v-if="tabInfo">
<p>set time limit for:</p>
<p>{{ tabInfo.url }}</p>
</div>
<div v-else> loading... </div>
</div>
</template>
<script>
export default {
data() {
return {
tabInfo: null,
};
},
mounted() {
this.getData();
},
methods: {
getData() {
chrome.tabs.query({ active: true, windowId: chrome.windows.WINDOW_ID_CURRENT }, function(tabs) {
console.log(tabs[0]);
this.tabInfo = tabs[0];
});
},
},
};
</script>
The console.log statement in my getData function writes the correct object in the console. But the template only shows the else case (loading...).
// EDIT EDIT
Found the error: I used 'this' in the callback function to reference my data but the context of this inside the callback function is an other one.
So the solution is to use
let self = this;
before the callback function and reference the data with
self.tab

Answer 1

You could initialize tab to null (instead of {}) and use v-if="tabs" in your template, similar to this:
// template
<template>
<div v-if="tab">
{{ tab.label }}
<p>{{ tab.body }}</p>
</div>
</template>
// script
data() {
return {
tab: null,
}
}
new Vue({
el: '#app',
data() {
return {
tab: null,
}
},
mounted() {
this.getData();
},
methods: {
getData() {
fetch('https://reqres.in/api/users/2?delay=1')
.then(resp => resp.json())
.then(user => this.tab = user.data)
.catch(err => console.error(err));
}
}
})
<script src="https://unpkg.com/vue#2.5.17"></script>
<div id="app">
<div v-if="tab">
<img :src="tab.avatar" width="200">
<p>{{tab.first_name}} {{tab.last_name}}</p>
</div>
<div v-else>Loading...</div>
</div>