如何将字符串拆分为重复的子字符串

function splitStringToRepeatedSubstrings(str) {
  if (str.length % 2 !== 0) {
    return "字符串长度必须为偶数";
  }

  var possibleSubstrings = [];
  for (var i = 1; i <= str.length / 2; i++) {
    if (str.length % i === 0) {
      possibleSubstrings.push(str.substr(0, i));
    }
  }

  for (var j = 0; j < possibleSubstrings.length; j++) {
    var repeatedString = possibleSubstrings[j].repeat(str.length / possibleSubstrings[j].length);
    if (repeatedString === str) {
      return "可以将字符串拆分为重复的子字符串";
    }
  }

  return "不能将字符串拆分为重复的子字符串";
}

console.log(splitStringToRepeatedSubstrings("abcabc"));  // 输出：可以将字符串拆分为重复的子字符串
console.log(splitStringToRepeatedSubstrings("abcab"));   // 输出：不能将字符串拆分为重复的子字符串