bad balancer code js

const out = document.getElementById('out');

const arr = [1, 4, 2, 5];
function sovle(arr) {
  const sum = arr.reduce((v, i) => v + i);
  precondition:
  if(sum % 2 === 1) {
    if(arr % 2 === 0) {
      return null;
    }
    for(let i = 0; i < arr.length; ++i) {
      if(arr[i] % 2 === 1) {
        arr.splice(i, 1);
        break precondition;
      }
    }
    return null;
  }

  const halfSum = sum / 2;
  const left = [];
  const right = [];
  for(let i = 0; i < arr.length; ++i) {
    for(let j = 0; j < arr.length; ++j) {
      if(i === j) {
        continue;
      }


    }
  }
}