being passed as $attr and not prop vue code example

Example 1: vue js default prop

props: {
  name: {
    type: String,
    default: 'John Doe'
  }
}

Example 2: vue passing props

<!-- Dynamically assign the value of a variable -->
<blog-post v-bind:title="post.title"></blog-post>

<!-- Dynamically assign the value of a complex expression -->
<blog-post
  v-bind:title="post.title + ' by ' + post.author.name"
></blog-post>