Every component instance has its own isolated scope. This means you cannot (and should not) directly reference parent data in a child component’s template. Data can be passed down to child components using props. Props are custom attributes you can register on a component. When a value is passed to a prop attribute, it becomes a property on that component instance.
Vue.component('blog-post', {
// camelCase in JavaScript
props: ['postTitle'],
template: '<h3>{{ postTitle }}</h3>'
})
