Get smallest string out of the array with nested arrays

I am trying to get the smallest string out of every nested array in the following array object

let data = ["test string", ["abcd", "efj", ["hijklm", ["op"], "hijk", "hijklmn", ["op", "opq"]]]]

I have tried the code but it gives me stackoverflow error,Any help please

let data = ["test string", ["abcd", "efj", ["hijklm", ["op"], "hijk", "hijklmn", ["op", "opq"]]]]

let smallest = []

function getSmallest(data) {


  data.forEach((ele, i) => {

    if (typeof ele == "string") {
      smallest.push(ele);
    } else if (typeof ele == "object") {
      // removing the array first
      let _data = JSON.parse(JSON.stringify(data));
      let only_array = _data.splice(i, 1);
      getSmallest(only_array)
      // now data contains only strings

      //finding the smalles string from array
      let small = _data.filter(v => typeof v === 'string')
        .reduce((a, v) => a && a.length <= v.length ? a : v, '')

      smallest.push(small);

    }


  });


}
getSmallest(data);
console.log(smallest)

Required result -Smallest in every array (nested one as well)

["test string",  "efj", "hijk", "op", "op"]

Answer

You could take a recursive approach.

const
    smallest = array => array
        .reduce((r, value) => {
            if (Array.isArray(value)) r.push(...smallest(value));
            else if (!r[0].length || r[0][0].length > value.length) r[0][0] = value;
            return r;
        }, [[]])
        .flat(),
    data = ["test string", ["abcd", "efj", ["hijklm", ["op"], "hijk", "hijklmn", ["op", "opq"]]]],
    result = smallest(data);

console.log(result);