Pass data from blade to vue and keep parent-child in sync? - vue.js

Question

I know that in Vue parents should update the children through props and children should update their parents through events.
Assume this is my parent component .vue file:
<template>
<div>
<my-child-component :category="category"></my-child-component>
</div>
</template>
<script>
export default {
data: {
return {
category: 'Test'
}
}
}
</script>
When I update the category data in this component, it will also update the category props in my-child-component.
Now, when I want to use Vue in Laravel, I usually use an inline template and pass the value from the blade directly to my components (as for example also suggested at https://stackoverflow.com/a/49299066/2311074).
So the above example my my-parent-component.blade.php could look like this:
#push('scripts')
<script src="/app.js"></script>
#endpush
<my-parent-component inline-template>
<my-child-component :category="{{ $category }}"></my-child-component>
</my-parent-component>
But now my-parent-component is not aware about the data of category. Basically only the child knows the category and there is no communication between parent and child about it.
How can I pass the data from blade without breaking the parent and child communication?

Answer 1

I just had to pass the category to the inline-template component through props like this:
#push('scripts')
<script src="/app.js"></script>
#endpush
<my-parent-component :initcategory="{$category}}" inline-template>
<my-child-component v-model="category"></my-child-component>
</my-parent-component>
In my-parent-component I had to set the props and initialize is using the create method:
export default {
props: {
initcategory: '',
},
data() {
return {
category: '',
};
},
created(){
this.category = this.initcategory;
}
}
Now my my-parent-component is fully aware of the category and it can communicate to the child using props and $emit as usual.

Answer 2

Your reference to this answer is different altogether from what you are looking for!
He's binding the :userId prop of the example component but not the parent component or in simple words: Any template using the example vue can either pass a string prop or bind :userId prop to a string variable. Following is similar:
<example :userId="{{ Auth::user()->id }}"></example>
OR
<example :userId="'some test string'"></example>
So you should rather assign {{ $category }} to a data variable but rather binds to a child component prop which will have no effect on the parent.
In the following snippet you're only binding the string but rather a data key:
<my-child-component :category="{{ $category }}"></my-child-component>
Update
See the following example which will change the h1 title after 3 seconds
// HelloWorld.vue
<template>
<app-name :name="appName" #appNameChanged="appName = $event"></app-name>
</template>
<script>
export default {
props: ['name'],
data() {
return {
appName: null
}
},
mounted() {
// NOTE: since Strings are immutable and thus will assign the value while objects and arrays are copied by reference
// the following is just for the purpose of understanding how binding works
this.appName = this.name;
}
}
</script>
The template which renders the app title or you can say the child component
// AppName.vue
<template>
<h1>{{ name }}</h1>
</template>
<script>
export default {
props: ['name'],
mounted() {
setTimeout(() => {
this.$emit('appNameChanged', 'Change App')
}, 3000);
}
}
</script>
And here's how it is being used in the welcome.blade.php
<div id="app">
<hello-world :name="'Laravel App'"></hello-world>
</div>