Randomize related posts in Docpad -

i've installed related plugin docpad , want want display 5 random related posts in sidebar of every blogpost. @ moment have set way in post.html.jade:

div   h4 related posts:   each doc in getrelateddocuments().slice(0,5)     a(href=doc.url)= doc.title     br 

so, displays 5 posts, aren't random. how shuffle output of getrelateddocuments()?

have tried variation on question getting random value array?

i created function in docpad.coffee file implement solution:

getrandomposts: (howmany) ->     items = @getcollection('posts').tojson()     output = []     = 0     while < howmany         doc = items[math.floor(math.random() * items.length)]         output.push(doc)         i++      return output 

you may need step in while loop check if doc value in output array math.floor etc possibly return value used.