My Blog built with Gatsby

Just found this weird behavior of different browsers...
Had problems sorting posts by date in Firefox, but Chrome worked alright.
Apparently firefox didn't understand dates in format 11-02-2021, but needed 11/02/2021.

This is my Fourth blog post.
Added some About me data, and sorting by created date. Newest posts at the top.
Blow is the code that executes sorting:

    data.allMarkdownRemark.edges
    .sort((a, b) => {
            const aDate = new Date(a.node.frontmatter.date);