if... !true conditional rendering in nunjucks

I see you've got a bit of a bobby dazzler here.

Try using not instead of !.

In other words, use not, not !!

Give 'er a go mate and notice that in the raw section here they highlight not as if it's a keyword.

https://mozilla.github.io/nunjucks/templating.html#raw

Best of luck to ye.

You can use the syntax:

<% '' if posts.length else 'No project posts yet!' %>

https://mozilla.github.io/nunjucks/templating.html#if-expression