Js Snowflake(雪花算法)生成随机ID的实现方法

1、snowflake-id插件

import SnowflakeId from "snowflake-id";

const guid = num => {
 const id= new SnowflakeId();
 return id.generate();
};

2、原生使用

var Snowflake = /** @class */ (function() {
	function Snowflake(_workerId, _dataCenterId, _sequence) {
		this.twepoch = 1288834974657n;
		//this.twepoch = 0n;
		this.workerIdBits = 5n;
		this.dataCenterIdBits = 5n;
		this.maxWrokerId = -1n ^ (-1n << this.workerIdBits); // 值为：31
		this.maxDataCenterId = -1n ^ (-1n << this.dataCenterIdBits); // 值为：31
		this.sequenceBits = 12n;
		this.workerIdShift = this.sequenceBits; // 值为：12
		this.dataCenterIdShift = this.sequenceBits + this.workerIdBits; // 值为：17
		this.timestampLeftShift = this.sequenceBits + this.workerIdBits + this.dataCenterIdBits; // 值为：22
		this.sequenceMask = -1n ^ (-1n << this.sequenceBits); // 值为：4095
		this.lastTimestamp = -1n;
		//设置默认值,从环境变量取
		this.workerId = 1n;
		this.dataCenterId = 1n;
		this.sequence = 0n;
		if(this.workerId > this.maxWrokerId || this.workerId < 0) {
			thrownew Error('_workerId must max than 0 and small than maxWrokerId-[' + this.maxWrokerId + ']');
		}
		if(this.dataCenterId > this.maxDataCenterId || this.dataCenterId < 0) {
			thrownew Error('_dataCenterId must max than 0 and small than maxDataCenterId-[' + this.maxDataCenterId + ']');
		}

		this.workerId = BigInt(_workerId);
		this.dataCenterId = BigInt(_dataCenterId);
		this.sequence = BigInt(_sequence);
	}
	Snowflake.prototype.tilNextMillis = function(lastTimestamp) {
		var timestamp = this.timeGen();
		while(timestamp <= lastTimestamp) {
			timestamp = this.timeGen();
		}
		return BigInt(timestamp);
	};
	Snowflake.prototype.timeGen = function() {
		return BigInt(Date.now());
	};
	Snowflake.prototype.nextId = function() {
		var timestamp = this.timeGen();
		if(timestamp < this.lastTimestamp) {
			thrownew Error('Clock moved backwards. Refusing to generate id for ' +
				(this.lastTimestamp - timestamp));
		}
		if(this.lastTimestamp === timestamp) {
			this.sequence = (this.sequence + 1n) & this.sequenceMask;
			if(this.sequence === 0n) {
				timestamp = this.tilNextMillis(this.lastTimestamp);
			}
		} else {
			this.sequence = 0n;
		}
		this.lastTimestamp = timestamp;
		return((timestamp - this.twepoch) << this.timestampLeftShift) |
			(this.dataCenterId << this.dataCenterIdShift) |
			(this.workerId << this.workerIdShift) |
			this.sequence;
	};
	return Snowflake;
}());

console.log(new Snowflake(1n, 1n, 0n).nextId());
//1141531990672150528n

控制台输出1141531990672150528n为bigint格式, .toString()转为字符串格式即可

3、ES6使用

import bigInt from "big-integer";

const guid = () => {
 const Snowflake = /** @class */ (function() {
  function Snowflake(_workerId, _dataCenterId, _sequence) {
   // this.twepoch = 1288834974657;
   this.twepoch = 0;
   this.workerIdBits = 5;
   this.dataCenterIdBits = 5;
   this.maxWrokerId = -1 ^ (-1 << this.workerIdBits); // 值为：31
   this.maxDataCenterId = -1 ^ (-1 << this.dataCenterIdBits); // 值为：31
   this.sequenceBits = 12;
   this.workerIdShift = this.sequenceBits; // 值为：12
   this.dataCenterIdShift = this.sequenceBits + this.workerIdBits; // 值为：17
   this.timestampLeftShift = this.sequenceBits + this.workerIdBits + this.dataCenterIdBits; // 值为：22
   this.sequenceMask = -1 ^ (-1 << this.sequenceBits); // 值为：4095
   this.lastTimestamp = -1;
   //设置默认值,从环境变量取
   this.workerId = 1;
   this.dataCenterId = 1;
   this.sequence = 0;
   if (this.workerId > this.maxWrokerId || this.workerId < 0) {
    throw new Error(
     'config.worker_id must max than 0 and small than maxWrokerId-[' + this.maxWrokerId + ']'
    );
   }
   if (this.dataCenterId > this.maxDataCenterId || this.dataCenterId < 0) {
    throw new Error(
     'config.data_center_id must max than 0 and small than maxDataCenterId-[' +
      this.maxDataCenterId +
      ']'
    );
   }
   this.workerId = _workerId;
   this.dataCenterId = _dataCenterId;
   this.sequence = _sequence;
  }
  Snowflake.prototype.tilNextMillis = function(lastTimestamp) {
   var timestamp = this.timeGen();
   while (timestamp <= lastTimestamp) {
    timestamp = this.timeGen();
   }
   return timestamp;
  };
  Snowflake.prototype.timeGen = function() {
   //new Date().getTime() === Date.now()
   return Date.now();
  };
  Snowflake.prototype.nextId = function() {
   var timestamp = this.timeGen();
   if (timestamp < this.lastTimestamp) {
    throw new Error(
     'Clock moved backwards. Refusing to generate id for ' + (this.lastTimestamp - timestamp)
    );
   }
   if (this.lastTimestamp === timestamp) {
    this.sequence = (this.sequence + 1) & this.sequenceMask;
    if (this.sequence === 0) {
     timestamp = this.tilNextMillis(this.lastTimestamp);
    }
   } else {
    this.sequence = 0;
   }
   this.lastTimestamp = timestamp;
   var shiftNum =
    (this.dataCenterId << this.dataCenterIdShift) |
    (this.workerId << this.workerIdShift) |
    this.sequence; // dataCenterId:1,workerId:1,sequence:0 shiftNum:135168
   var nfirst = new bigInt(String(timestamp - this.twepoch), 10);
   nfirst = nfirst.shiftLeft(this.timestampLeftShift);
   var nnextId = nfirst.or(new bigInt(String(shiftNum), 10)).toString(10);
   return nnextId;
  };
  return Snowflake;
 })();

 return new Snowflake(1, 1, 0).nextId();
};

guid()即可调用

4、多次重复调用出现一样id的bug

  console.log(guid(), new Date().getTime());
  console.log(guid(), new Date().getTime());
  console.log(guid(), new Date().getTime());
  console.log(guid(), new Date().getTime());
  console.log(guid(), new Date().getTime());
  console.log(guid(), new Date().getTime());
  console.log(guid(), new Date().getTime());
  console.log(guid(), new Date().getTime());
  console.log(guid(), new Date().getTime());
  console.log(guid(), new Date().getTime());
  console.log(guid(), new Date().getTime());
  console.log(guid(), new Date().getTime());

修改如下

import SnowflakeId from "snowflake-id";

const guid = num => {
 const snowflake = new SnowflakeId();
 let arr = [];
 for (let i = 0; i < num; i++) {
  arr.push(snowflake.generate());
 }
 return num ? arr : snowflake.generate();
};

单个调用 guid()

n个调用 guid(n)

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