Laravel - displaying categories by id - php

Question

For a blog site, I have all the posts & lists of categories displaying on a page though now I need to display the posts for each category on it's own separate page.
Let's say I had a categorie that was 'Javascript' and I wanted only the posts with the category of javascript displayed on a page.
What's the correct code to do this? here's an example, the bold 'javascript' is what needs to be replaced with the correct code.
-- categoriesController.php ---
public function show($id)
{
$post->withCategories($Categories)->$id->($id as **javascript)**
}
--- javascript.blade.php --- ( corresponding view )
<tbody>
#foreach ($categories as $category->$id>**javascript**)
<tr>
<th>{{ $category->id }}</th>
<td>{{ $category->name }}</td>
</tr>
#endforeach
</tbody>
</table>
</div> <!-- end of .col

Answer 1

For example:
post.php model
class Post extends Model
{
protected $primaryKey = 'id';
function withCategories() {
return $this->hasOne('App\Categories', 'id', 'category_id');
}
public function show($id){
Post::with('withCategories')->where('category_id', $id)->get(); //the output of articles of the category
}
}
$id is a parameter of url: site.com/posts/javascript
in posts.blade.php
<table>
<tbody>
#foreach ($posts as $post)
<tr>
<th>{{ $post->id }}</th>
<td>{{ $post->name }}</td>
<td>{{ $post->withCategories->name }}</td> <!-- Category name-->
</tr>
#endforeach
</tbody>
</table>
</div>