finding elem in sorted Array very naive approach (probably)

//Probably a Naive solution

const sortedArr = [1,2,3,7,9,15,56,76,78];

function findElem(arr, n){
    const firstHalf  =  arr.slice(0, arr.length / 2),
        secondHalf =  arr.slice(arr.length / 2);
    let arrToPass;
   
    if (arr.length === 1 && arr[0] !== n){
        return false
    }
    else{
        if (arr[0] === n){
            return true
        }
        if (secondHalf[0] > n ){
            arrToPass = firstHalf;
        } 
        else {
            arrToPass = secondHalf;
        }   
        return findElem(arrToPass, n)   
    }
}
console.log(findElem(sortedArr, 15)) // => true

console.log(findElem(sortedArr, 78)) // => true

console.log(findElem(sortedArr, 9)) // => true
console.log(findElem(sortedArr, 89)) // => false
console.log(findElem(sortedArr, 111)) // => false