LeetCode|724. Find Pivot Index

let result = -1;

let sum = function(arr){
    return arr.reduce((prev,curr)=>(prev+curr),0);
}

for (let i = 0; i < nums.length; i++){
    
    let left = nums.slice(0,i);
    let right = nums.slice(i+1,nums.length);
    
   if(sum(left)===sum(right)){
       result = i;
       return result;
   }   
}
return result;