snowflake/index.js
2024-02-06 06:10:46 +01:00

72 lines
1.8 KiB
JavaScript

class Snowflake {
constructor(machineId) {
if (machineId < 0 || machineId >= 1024) {
throw new Error("Machine ID must be in the range 0-1023.");
}
this.machineId = BigInt(machineId);
this.sequence = BigInt(0);
this.lastTimestamp = BigInt(-1);
this.timestampShift = 22n;
this.machineIdShift = 12n;
this.sequenceMask = 0xfffn;
}
async generate() {
let timestamp = BigInt(Date.now());
if (timestamp === this.lastTimestamp) {
this.sequence = (this.sequence + 1n) & this.sequenceMask;
if (this.sequence === 0n) {
while (timestamp <= this.lastTimestamp) {
await new Promise((resolve) => setTimeout(resolve, 1));
timestamp = BigInt(Date.now());
}
}
} else {
this.sequence = 0n;
}
this.lastTimestamp = timestamp;
const id =
((timestamp & 0x1ffffffffffn) << this.timestampShift) |
(this.machineId << this.machineIdShift) |
this.sequence;
return id.toString();
}
}
function decodeSnowflake(idStr) {
const id = BigInt(idStr);
const timestampShift = 22n;
const machineIdShift = 12n;
const sequenceMask = 0xfffn;
const timestamp = (id >> timestampShift) & 0x1ffffffffffn; // Adjusting the shift
const machineId = (id >> machineIdShift) & 0x3ffn;
const sequence = id & sequenceMask;
const date = new Date(Number(timestamp)); // Converting BigInt to Number, then to Date
return {
timestamp: date.toISOString(),
machineId: machineId.toString(),
sequence: sequence.toString(),
};
}
// Use
(async () => {
const machineId = 1; // machine ID (0-1023)
const snowflake = new Snowflake(machineId);
const id1 = await snowflake.generate();
console.log("encodeID", id1);
const decoded = decodeSnowflake(id1);
console.log("decodeID", decoded);
})();