Student of The Odin Project Here

https://github.com/TheOdinProject/javascript-exercises/tree/solutions/sumAll

I managed to get the sum part of it work (so it's only the first if statement that is the problem)

They want "ERROR" returned if a non-number is passed as either a or b , or if a or b is a negative number.

I used the code below.

First if statement is evaluating to true even if both a and b are numbers

Their solution was to use !Number.isInteger(a)||!Number.isInteger(b)

Any ideas why the first if statement done as below does not work as intended

If I console.log(a) it logs number

const sumAll = function(a,b) {
    let c =0
    if((a||b)<0 || (typeof(a)||typeof(b)) !=Number){
        return "ERROR"
    }
    else if(a<b){
   for(let i=a; i<=b; i  ){
       c  = i;
   }
   return c ;
   }else if(a>b){for(let i=b; i<=a; i  ){
    c  = i;
   }
   return c;
   }
   };

CodePudding user response：

If you want to individually check for a<0 and b<0, you cannot do (a||b)<0. Reason: a||b gets evaluated first and you get the first truthy value out of a and b. So, it becomes a matter of order. If you pass 1,-2 you will get 1 as your result of a||b and obviously 1<0 return false.

function func(a,b){
console.log(a||b);
console.log((a||b)<0);
}

func(1,-2);
func(-1,2);
func(1,2);

Similar problem with (typeof(a)||typeof(b)) !=Number. You are supposed to individually check ((typeof(a) != 'number') || (typeof(b) != 'number')). Notice how I have changed Number to 'number'. typeof returns a string as mentioned in comments.

You need to amend your if conditions accordingly.