如何展平数组并分配新的键？(TS，JS)

function flattenArray(arr: any[]): any[] {
  let result: any[] = [];
  
  arr.forEach((item) => {
    if (Array.isArray(item)) {
      result = result.concat(flattenArray(item)); // 递归展平子数组
    } else {
      result.push(item);
    }
  });
  
  return result;
}

function assignKeys(arr: any[]): { [key: string]: any }[] {
  const flattenedArr = flattenArray(arr);
  const assignedArr = flattenedArr.map((item, index) => ({ key: index, value: item }));
  
  return assignedArr;
}

const originalArray = [[1, 2], [3, 4], [5, 6]];
const flattenedAndAssignedArray = assignKeys(originalArray);

console.log(flattenedAndAssignedArray);