Remove Multiple New Lines with JavaScript

I'm blessed in that lots of people want to guest post on this blog. It's really flattering and I love seeing writers get a bunch of attention after writing. My task is converting the blog post, in whatever format it's provided in (HTML, Markdown, PDF, Google Doc, etc.), to HTML for my blog, which can sometimes get messy. I employ a host of regular expressions to fix these formatting issues. And the number one problem? Loads of extra new lines (\n).