gistfile1.js

function(dest, src){
  // Split the src into an array of path components
  srcComponents = src.split("/")
  
  // Cut out the second to last one
  srcComponents.splice(srcComponents.length - 2, 1)
  
  // Join the path components back together into a path
  newSrc = srcComponents.join("/")
  
  return dest + newSrc
}