custom-unique-id-generator

A simple and customizable package to generate persistent, sequential, human-readable unique IDs with configurable prefixes and storage options (file or in-memory).

Features

• Generate sequential IDs with a custom prefix and total length (e.g., ABC0001, HOD1021)
• Supports persistent storage in JSON files or in-memory storage
• Safe for concurrent use with basic locking
• Easy to integrate in Node.js projects
• Lightweight and configurable

Installation

npm install custom-unique-id-generator

Basic Usage

import { PersistentUniqueIDGenerator } from 'custom-unique-id-generator';

const generator = new PersistentUniqueIDGenerator({ prefix: "INV", totalLength: 7, storage: { type: "file", filePath: "./invoice-counter.json" } });

const id = await generator.generate(); // Returns: "INV0001"

Sequelize Integration Example

hooks: { beforeCreate: async (record) => { if (!record.id) { record.id = await generator.generate(); } } }

CLI Usage Example (if added later)

npx custom-unique-id-generator --prefix=USR --length=6

All Options Documented

| Option | Type | Description | |--------|------|-------------| | prefix | string | Prefix for generated ID (e.g., USR) | | totalLength | number | Total length including prefix (e.g., 6 → USR001) | | storage.type | "file" or "memory" | Storage backend | | filePath | string | (Required if type=file) Path to store counter |

Example: Generate multiple IDs

async function generateMultiple() { for (let i = 0; i < 10; i++) { const id = await generator.generate(); console.log("Generated ID:", id); } }

generateMultiple();

sample table stacher

import { DataTypes, } from 'sequelize'; import { PersistentUniqueIDGenerator } from "custom-unique-id-generator";

// Create a unique ID generator instance const generator = new PersistentUniqueIDGenerator({ prefix: "POR", totalLength: 6, // Example: POR001 storage: { type: "file", filePath: "./counter-data.json", }, });

export default (sequelize) => {

  const attributes = {
      purchase_order_id: { type: DataTypes.STRING, primaryKey: true },

      type: { type: DataTypes.STRING, defaultValue: null },

      attachment: { type: DataTypes.JSONB, defaultValue: [] },

      company: { type: DataTypes.STRING, defaultValue: null },

      date: { type: DataTypes.DATE, defaultValue: null },

      po_number: { type: DataTypes.STRING, defaultValue: null },

      created_by: { type: DataTypes.STRING, defaultValue: null, },

      updated_by: { type: DataTypes.STRING, defaultValue: null, },

      created_on: { type: DataTypes.DATE, defaultValue: DataTypes.NOW, },

      updated_on: { type: DataTypes.DATE, defaultValue: null },

  };

  const PurchaseOrder = sequelize.define('purchase_order', attributes, {
      tableName: 'purchase_order',
      timestamps: false,
      hooks: {
          beforeCreate: async (purchaseOrder: any) => {
              if (!purchaseOrder.purchase_order_id) {
                  purchaseOrder.purchase_order_id = await generator.generate();
              }
          },
      },
  });

    // Reset counter if table is empty (run once on model initialization)
  (async () => {
      try {
          await sequelize.authenticate();
          const count = await PurchaseOrder.count();
          if (count === 0) {
              await generator.resetIfTableIsEmpty(true);
          }
      } catch (err) {
          console.error('Error initializing purchase_order:', err);
      }
  })();

  return PurchaseOrder;

};

License

MIT License

Contributing

Contributions, issues, and feature requests are welcome!

Author

Jothi Manikandan