Determine if the user input is a number

function isValueNumber(val){
  let value = val.replace('/(^\s*)|(\s*$)','') //Remove spaces before and after the string
  let num = Number(value) // convert string to number
  if(isNaN(num)){ //Determine whether it is a non-number
    return false
  }else if(value === ''|| value === null){ //Empty strings and nulls are both treated as numbers
    return false
  }else{
    return true
  }
}