I have the following function in my app. It works correctly in the other browsers but does not function in safari.

  function left(event){
        let i = document.getElementById("symb").innerText;
        let x = oldArray.find(e => e.symbol == i);
        let index = oldArray.indexOf(x);
        alert(i)
        if (index != 0){
            loadPage(oldArray[index - 1].id)
        }else{
            loadPage(oldArray[oldArray.length - 1].id)
        }
     }

variable i comes thru correctly but the find portion returns undefined for x.