They show what you can do, and that you are able to solve problems. Maybe the editor plugin is not doing that. A cool demo is worth more than a thousand lines of well written code.
I work for a company now that frequently interviews front end/js devs and frankly if we find ANY github/public code it puts you in the lead above the next guy. What you normally write doesn't matter a whole lot because most concepts transfer to any language.
Most of our applicants give us no previous code they have actually written. I fail to see how it can ever be argued that something < nothing.
javascript is typically something you shouldnt focus on as open source experience imo. so many people doing it and doing it badly for feelsy points.
you think the person who wrote nginx wouldnt get hired? something mission critical that alot of businesses use.