code: function inArray(value, arr) {
      let len = arr.length;
      for (let i = 0; i < len; i++) {
          if (arr[i] == value) {
              return true;
          }
      }
      return false;
  }
docs: Determines whether value is an element of array arr,
  only determine the same value with the element, do not determine the type
  @param {any} value
  @param {any[]} arr
  @returns {boolean}