Adding object properties in JavaScript -

i trying subtract value of object1's objectproperty object2's object property , keep getting nan on console. here example code:

    object1.objectproperty - object2.object2property 

if isn't enough go off, can post full code project. if there way or kind of function can help, please let me know.

edit: here code..

    var mypokemon = {     health: 25,     defense: 5,     attack: 10,     speed: 5 };  var moves = {     scratch: 5,     bite: 5,     slap: 5,     growl: 1 };   var computerpokemon = {     health: 20,     defense: 5,     attack: 10,      speed: 7 };  function calcdamage(firstpokemon, secondpokemon, move) {     if(move == moves.growl){         //starts here         var newdefense =  moves.growl - firstpokemon.defense;         console.log(newdefense);         //ends here     }else{     var newhealth = (firstpokemon.health + firstpokemon.defense) - (secondpokemon.attack + move);     console.log(newhealth);     } } 

edit: when did moves.growl - firstpokemon.defense || 0; returned -4 instead of nan wanted do, person answered removed answer has been answered whoever guy was.

the problem adding object in second argument. if statement never execute, have fixed both following

        var mypokemon = {      	health: 25,      	defense: 5,      	attack: 10,      	speed: 5      };            var moves = {      	scratch: 5,      	bite: 5,      	slap: 5,      	growl: 1      };                  var computerpokemon = {      	health: 20,      	defense: 5,      	attack: 10,       	speed: 7      };            function calcdamage(firstpokemon, secondpokemon, move) {      	if(moves.growl!=undefined){              //starts here      		var newdefense =  moves.growl - firstpokemon.defense;      		alert(newdefense);              //ends here      	}else{      	var newhealth = (number(firstpokemon.health) + number(firstpokemon.defense)) - (number(secondpokemon.attack) + number(move.growl));      	alert(newhealth);          }      }    calcdamage(mypokemon,computerpokemon,moves)