Js 雪花算法生成随机ID Js Snowflake(雪花算法)生成随机ID的实现方法
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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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