Answer 1

神仙题，，，看不懂咋办

Answer 2

/**
 * @param {number} idx 开始删除的索引
 * @param {number} deleteCount 需要删除的数目
 * @param {any[]} insertItems 需要插入项
 * @returns {any[]} 被删的数组项的数组
 */
Array.prototype.mySplice = function (idx, deleteCount) {
  var arr = this;
  var length = arr.length;
  var insertItems = [].slice.call(arguments, 2);
  deleteCount =
    typeof deleteCount !== 'undefined' && deleteCount <= length - idx
      ? deleteCount
      : length - idx;
  var res = [];
  while (deleteCount) {
    deleteCount--;
    if (idx in arr) {
      res.push(arr[idx]);
    }
    for (var i = idx; i < arr.length - 1; i++) {
      arr[i] = arr[i + 1];
    }
    arr.length = arr.length - 1;
  }
  for (var j = 0; j < insertItems.length; j++) {
    arr.push(insertItems[j]);
  }
  return res;
};

写了一个TS的，编译了下

Answer 3

看到两个小的笔误：

Answer 4

/**
 * @description 用最精炼的代码实现数组非零最小值 index
 * @param {array} arr 数组
 * @returns {number} index 索引
 */
function getIndex(arr) {
      let index = -1;
      const minVal = arr.reduce((cur, pre) => {
            return (cur <= 0 || pre <= 0) ? Math.max(cur, pre) : cur > pre ? pre : cur;
      }, -1);
      index = arr.findIndex(item => item == minVal && minVal > 0)
      return index;
}