Javascript 如何在meteor中生成4位字母数字代码？

如何在Meteor中生成不重复的4位字母数字代码？

您要求4位数字，但也会说“字母数字”。无论哪种方式：

function generate4DigitNonRepeatingNumericCode() {
  ret = "";
  while (ret.length < 4) {
    var pickANumberBetween0and9 = ("" + Math.random()).charAt(2);
    if (ret.indexOf("" + pickANumberBetween0and9) == -1)
      ret += pickANumberBetween0and9;
  }
  return ret;
}

---

因为您可以添加npm支持。为什么不使用hashids这样的库呢？

function generate4CharacterNonRepeatingAlphanumericCode() {
  ret = "";
  while (ret.length < 4) {
    var pickACharacter = ("" + 
      new Meteor.Collection.ObjectID().toHexString()).charAt(0);
    if (ret.indexOf("" + pickACharacter) == -1)
      ret += pickACharacter;
  }
  return ret;
}