Data Validation Proximity

A comprehensive library of Joi-based validation middlewares for Express.js applications, specifically designed for e-commerce platforms with complex data structures.

Installation

npm install data-validation-proximity

Dependencies

This package requires Joi for validation:

npm install joi@^17.x

Usage

Basic Setup

const express = require('express');
const { 
  validateUser, 
  validateProduct, 
  validateStore 
} = require('data-validation-proximity');

const app = express();
app.use(express.json());

// Apply validation middleware to routes
app.post('/api/users', validateUser, (req, res) => {
  // req.body is validated
  res.json({ message: 'User created' });
});

app.post('/api/products', validateProduct, (req, res) => {
  // req.body is validated and preprocessed
  res.json({ message: 'Product created' });
});

app.post('/api/stores', validateStore, (req, res) => {
  // req.body is validated
  res.json({ message: 'Store created' });
});

Available Validation Middlewares

User & Authentication

• validateUser - Validates user registration/creation
• validateUserUpdate - Validates user profile updates
• validateLogin - Validates login credentials
• validateResetPassword - Validates password reset requests

Store Management

• validateStore - Validates store creation with full details
• validateStoreUpdate - Validates store information updates
• validateStoreCategory - Validates store category data
• validateStoreRate - Validates store rating submissions

Product Management

• validateProduct - Validates product creation with images and variants
• validateProductUpdate - Validates product updates
• validateCategory - Validates product category data

Orders & Transactions

• validateOrder - Validates order placement
• validateCart - Validates shopping cart data
• validateBill - Validates billing information
• validatePayment - Validates payment transactions
• validatePaymentType - Validates payment method types

Promotions & Offers

• validateOffer - Validates special offers/promotions
• validateFlashDeal - Validates flash sale deals
• validateReductionOffer - Validates discount offers

Subscriptions

• validatePlan - Validates subscription plans
• validateSubscription - Validates subscription data
• validateSubscriptionOffer - Validates subscription offer details

Other

• validateNotification - Validates notification data
• validateSale - Validates sales records
• validateView - Validates view tracking data
• validateUserAction - Validates user activity tracking

Features

Automatic Data Preprocessing

The library includes intelligent preprocessing for complex data:

JSON Field Parsing

Automatically parses stringified JSON fields:

// Before validation, string fields are parsed to objects
app.post('/api/products', validateProduct, (req, res) => {
  // req.body.variants: "[{...}]" → [{...}]
  // req.body.policy: "{...}" → {...}
});

File Array Normalization

Normalizes file uploads for consistent handling:

// Single file uploads are converted to arrays
app.post('/api/products', validateProduct, (req, res) => {
  // req.files.images: single file → [file]
  // req.files.varientsImages: single file → [file]
});

Complex Schema Support

Address Schema

{
  latitude: Number,
  longitude: Number,
  countryCode: String (min 2 chars),
  country: String (min 3 chars),
  city: String (min 3 chars),
  streetName: String (min 3 chars),
  postalCode: String (min 3 chars),
  fullAdress: String,
  region: String,
  apartmentNumber: String
}

Working Time Schema

{
  option: String (required),
  fixedHours: [{
    openTime: String,
    closeTime: String
  }],
  customizedHours: {
    [dayName]: [{
      openTime: String,
      closeTime: String
    }]
  }
}

Policy Schema

Comprehensive policy validation for:

• Working hours
• Pickup policies
• Delivery options
• Reservation rules (duration, payment, cancellation)
• Return policies (duration, conditions, refunds)
• Order management (validation, notifications)

Role Validation

Built-in support for role-based validation:

// Valid roles: 'user', 'admin', 'seller', 'paymentManager', 'manager', 'SuperManager'

Examples

User Registration

const { validateUser } = require('data-validation-proximity');

app.post('/api/register', validateUser, async (req, res) => {
  // req.body contains validated data:
  // - username, email, password, phone
  // - optional: address, profileImage, etc.
  const user = await User.create(req.body);
  res.status(201).json(user);
});

Product Creation

const { validateProduct } = require('data-validation-proximity');

app.post('/api/products', validateProduct, async (req, res) => {
  // Automatically preprocessed:
  // - JSON strings parsed to objects
  // - File arrays normalized
  // - Validated: name, price, category, variants, policy
  const product = await Product.create(req.body);
  res.status(201).json(product);
});

Store Setup

const { validateStore } = require('data-validation-proximity');

app.post('/api/stores', validateStore, async (req, res) => {
  // Validated data includes:
  // - store details (name, description, category)
  // - address with coordinates
  // - working hours
  // - policies
  // - payment methods
  const store = await Store.create(req.body);
  res.status(201).json(store);
});

Order Placement

const { validateOrder } = require('data-validation-proximity');

app.post('/api/orders', validateOrder, async (req, res) => {
  // Validated: products, amounts, addresses, payment info
  const order = await Order.create(req.body);
  res.status(201).json(order);
});

Error Handling

Validation errors return a 400 status with detailed error messages:

// Invalid request
{
  "error": "\"email\" must be a valid email"
}

// Multiple validation errors
{
  "error": "\"price\" must be a positive number"
}

Integration with Custom Error Library

Works seamlessly with custom-error-library:

const { errorMiddleware } = require('custom-error-library');
const { validateProduct } = require('data-validation-proximity');

app.post('/api/products', validateProduct, createProduct);

// Error middleware handles validation errors
app.use(errorMiddleware);

Advanced Usage

Custom Validation Middleware

You can create custom validation middlewares using the exported helper:

const { createValidationMiddleware } = require('data-validation-proximity');
const Joi = require('joi');

const customSchema = Joi.object({
  customField: Joi.string().required()
});

const validateCustom = createValidationMiddleware(customSchema);

app.post('/api/custom', validateCustom, handler);

Preprocessing Hooks

For complex data transformations, validation middlewares include preprocessing:

// Example: Product validation with preprocessing
// 1. Parses JSON strings (variants, policy, etc.)
// 2. Normalizes file arrays
// 3. Validates against schema
// 4. Passes to route handler

Best Practices

1. Apply validation early - Use validation middleware before business logic
2. Combine with error handling - Use with custom-error-library for consistent errors
3. Use appropriate validators - Choose specific validators (validateUser vs validateUserUpdate)
4. Handle file uploads - Validation automatically normalizes file arrays
5. Trust preprocessed data - Data is cleaned and parsed before validation

Schema Reference

Common Field Types

| Field Type | Validation Rules | Example | |------------|-----------------|---------| | Email | Valid email format | [email protected] | | Phone | String, min 8 chars | +1234567890 | | Password | String, min 6 chars | securePass123 | | Price | Positive number | 29.99 | | Coordinates | Number (lat/lng) | 34.0522, -118.2437 | | URL | Valid URL format | https://example.com | | Role | Enum of valid roles | seller, admin |

License

MIT