If you followed the video tutorial to the end and do not see the site displaying the previews for mario's blogs, the simple issue is that 'blog' is suppose to be 'blogs'.
<BlogList blogs={blogs.filter(blog => blog.author === 'mario')} title="Mario's Blogs" />
=>
<BlogList blogs={blogs.filter(blogs => blog.author === 'mario')} title="Mario's Blogs" />
If you followed the video tutorial to the end and do not see the site displaying the previews for mario's blogs, the simple issue is that 'blog' is suppose to be 'blogs'.
<BlogList blogs={blogs.filter(blog => blog.author === 'mario')} title="Mario's Blogs" />
=>
<BlogList blogs={blogs.filter(blogs => blog.author === 'mario')} title="Mario's Blogs" />