Array.prototype.unique and count

Array.prototype.unique = function() {

    var o = {}, i, l = this.length, r = [];

   

  for(i=0; i<l;i+=1) 

if(!o[this[i]]) o[this[i]] = {"key": this[i], "value":1};

else o[this[i]] = {"key": this[i], "value":o[this[i]].value+1};

   

for(i in o) 

r.push({"key": o[i].key, "value": o[i].value});

   

return r;

};