Open external links in new tab with Goldmark markdown renderer in Hugo

Goldmark doesn’t have this feature by default, but it’s easy to add.

Agrim Prasad explains it in this post, thanks Agrim.

TLDR: Create a file at themes/bilberry-hugo-theme/layouts/_default/_markup/render-link.html with the following content:

<a href="{{ .Destination | safeURL }}"{{ with .Title}} title="{{ . }}"{{ end }}{{ if strings.HasPrefix .Destination "http" }} target="_blank"{{ end }}>{{ .Text | markdownify }}</a>

Now for any markdown links you write, if the URL is absolute (i.e. starts with http* rather than just a relative link like /example) then the resulting HTML a tag will have the target="_blank" property. You can add other protocols if you commonly link to ftp://, for example.

Note the addition of | markdownify }} at the end. This is required if you want to style your links (e.g. bold, italics) inside your markdown.