Ask HN: Hiring managers – what do you want to see in a candidate's portfolio?

I'm going to start looking for a new full-stack developer job in a few weeks and I thought it would be a good idea to get a portfolio together. I'd love to hear from hiring managers (and recruiters) what they want from a candidate's portfolio in terms of what should and shouldn't be on there?

A little spiel about me and a showcase of my projects of course is important. How important is the design? Highlights of code samples? Detailed case studies? I'm not sure what I should prioritise beyond the basics.