Mongoose Payload Validator (Express.js)

A middleware for validating request payloads against a Mongoose schema in Express.js applications using JavaScript. This package ensures the incoming request body adheres to the Mongoose schema structure, type definitions, and required constraints.

Features

• Express.js Only: This middleware is designed specifically for Express.js applications.
• Validates payloads against a Mongoose schema.
• Supports nested objects, arrays, and enums.
• Handles required fields and type validation.
• Easy-to-use as Express middleware.

Installation

Install via npm:

npm install mongoose-schema-custom-validator

Usage

1. Import the validatePayload middleware.
2. Pass the Mongoose schema and options.
3. Use it in your Express routes.

Example

const express = require("express");
const mongoose = require("mongoose");
const validatePayload = require("mongoose-schema-custom-validator");

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

// Define a Mongoose schema
const userSchema = new mongoose.Schema({
  name: { type: String, required: true },
  email: { type: String, required: true },
  age: { type: Number },
  role: { type: String, enum: ["admin", "user", "guest"] },
});

// Middleware to validate request body
app.post("/user", validatePayload(userSchema), (req, res) => {
  res.json({ message: "User data is valid!" });
});

app.listen(3000, () => {
  console.log("Server is running on port 3000");
});

Nested Objects and Arrays

const postSchema = new mongoose.Schema({
  title: { type: String, required: true },
  author: {
    name: { type: String, required: true },
    email: { type: String, required: true },
  },
  tags: [{ type: String }],
});

// Apply middleware
app.post("/post", validatePayload(postSchema), (req, res) => {
  res.json({ message: "Post data is valid!" });
});

Error Responses

When validation fails, the middleware responds with a detailed error message:

• 400 BadRequestError: If the request body is empty or not provided.
• 422 UnprocessableEntityError: If the payload fails validation.

Example error response:

{
  "error": {
    "statusCode": 422,
    "name": "UnprocessableEntityError",
    "message": "The request body is invalid. See error object `details` property for more info.",
    "details": [
      {
        "path": "email",
        "message": "must have required property 'email'"
      },
      {
        "path": "age",
        "message": "must be of type 'number', received 'string'"
      }
    ]
  }
}

License

This project is licensed under the MIT License. See the LICENSE file for details.

This version clearly states that the middleware is specifically for use in Express.js with JavaScript