PrimaryNav: Each child in array should have unique "key"

[poohbers]

This is a small bug in the PrimaryNav.js component, but wanted to share. Basically you need to add a key prop whenever you are mapping an array. For me, I'm simply using key={post.frontmatter.title}. This works for my project but probably not a great long term solution.

I added the key prop within the map function.