Form Request

Laravel-inspired request validation for Express.

Simple, clean, and developer-friendly validation with automatic 422 responses and validated data extraction.

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Installation

npm install @caplab/form-request

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Quick Example

import express from "express";
import { validation } from "@caplab/form-request";

const app = express();

app.use(express.json());
app.use(validation());

app.post("/register", async (req, res) => {
	await req.validate({
		email: "required|email",
		password: "required|min:6",
	});

	const data = req.validated();

	res.json({
		success: true,
		data,
	});
});

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Why Form Request?

Validation in Express is often verbose or fragmented across middleware.

Form Request brings a Laravel-style validation experience to Express:

• Laravel-like validation syntax
• Automatic 422 JSON responses
• Clean validated data extraction
• Removes unvalidated fields automatically
• Inline validation or class-based requests
• Works with both JavaScript and TypeScript

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Features

• Pipe-style validation rules

'email': 'required|email|min:5'

• Automatic validation error responses
• req.validated() returns only validated fields
• Nested object validation
• Array wildcard validation
• Custom validation rules
• Custom error messages
• TypeScript support
• FormRequest classes

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Basic Usage

Inline Validation

app.post("/login", async (req, res) => {
	const data = await req.validate({
		email: "required|email",
		password: "required|min:6",
	});

	res.json(data);
});

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FormRequest Classes

import { FormRequest } from "@caplab/form-request";

class RegisterRequest extends FormRequest {
	rules() {
		return {
			email: "required|email",
			password: "required|min:6",
		};
	}

	messages() {
		return {
			"email.required": "Email is required",
			"email.email": "Email must be valid",
		};
	}
}

app.post("/register", async (req, res) => {
	await req.validate(RegisterRequest);

	const data = req.validated();

	res.json(data);
});

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Validated Data Only

Extra fields are automatically removed.

Request body:

{
	"email": "john@example.com",
	"password": "123456",
	"is_admin": true
}

Validated result:

const data = req.validated();

Output:

{
	"email": "john@example.com",
	"password": "123456"
}

---

Nested Validation

await req.validate({
	"user.email": "required|email",
	"user.name": "required",
	"users.*.email": "required|email",
});

---

Custom Rules

import { extend } from "@caplab/form-request";

extend("phone", async (value) => {
	return /^\d{10}$/.test(value);
});

await req.validate({
	phone: "required|phone",
});

---

Custom Messages

await req.validate(
	{
		email: "required|email",
	},
	{
		attributes: {
			email: "email address",
		},
	},
);

Response:

{
	"message": "The email address field is required."
}

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Available Rules

Rule	Description
required	Field is required
nullable	Field may be null
string	Must be a string
number	Must be a number
integer	Must be an integer
boolean	Must be a boolean
array	Must be an array
object	Must be an object
email	Must be a valid email
min:n	Minimum value or length
max:n	Maximum value or length
same:field	Must match another field
confirmed	Requires {field}_confirmation

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Example Validation Error

{
	"message": "The given data was invalid.",
	"errors": {
		"email": ["The email field is required."]
	}
}

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License

MIT