Comment by nodesocket

Interestingly the results from jsc, are different from node.js:

----- jsc ------

   [] + []
   
   > [] + {}
   [object Object]
   > {} + []
   0
   > {} + {}
   NaN

------ node.js ------

   > [] + []
   ''
   > [] + {}
   '[object Object]'
   > {} + []
   '[object Object]'
   > {} + {}
   '[object Object][object Object]'