node-easyvalid/README.md

A lightweight, powerful validation library for Node.js backend development. Simplify user input validation, error handling, and data integrity in Express APIs and JavaScript applications with ease.

# Node EasyValid

A lightweight, powerful validation library for Node.js backend development. Simplify user input validation, error handling, and data integrity in Express APIs and JavaScript applications with ease.

## Features
- Truthy/falsy value checks
- Array validation for multiple inputs
- Email format validation
- String length constraints
- Numeric value validation
- Custom error messages and HTTP status codes
- Seamless integration with Express.js and other Node.js frameworks

## Installation

```bash
npm install node-easyvalid
```
## Quick Start
### Basic usage example:

```javascript
const { isTrue, isEmail, minLength } = require("node-easyvalid");

try {
    isTrue("hello", "Value is required"); // Passes
    isEmail("user@example.com", "Invalid email"); // Passes
    minLength("password123", 8, "Password too short"); // Passes
    isTrue("", "Cannot be empty"); // Throws Error
} catch (error) {
    console.log(error.message); // Custom error message
    console.log(error.statusCode); // Default 400 or custom
}
```


## 1. isTrue(value, [message], [statusCode])

What it does: Checks if something exists (not empty, not zero, not nothing).

Syntax:
value: The thing you’re checking (like a name or number).
message (optional): What to say if it fails (default: "Validation Failed").
statusCode (optional): A number for errors (default: 400, good for web apps).

Returns: true if okay, or throws an error if not.

Example

```javascript
const { isTrue } = require("node-easyvalid");

try {
  let name = 'John';
  let emptyValue = "";
  isTrue(name, "Name is missing!"); // Returns true
  isTrue(emptyValue, "Name is missing!"); // Throws "Name is missing!"
} catch (error) {
  console.log(error.message); // "Name is missing!"
}
```

## 2. isTrues(array, [message], [statusCode])
What it does: Makes sure every item in a list exists (not empty or nothing).

Syntax:
array: A list of things (like ["apple", "banana"]).
message (optional): Error message if something’s wrong (default: "Validation Failed").

statusCode (optional): Error number (default: 400).

Returns: true if all items are okay, or throws an error if not.
Example:
```javascript
const { isTrues } = require("node-easyvalid");

try {
  isTrues(["cat", "dog"], "List can’t have empty items!"); // Returns true
  isTrues(["cat", ""], "List can’t have empty items!"); // Throws error
} catch (error) {
  console.log(error.message); // "List can’t have empty items! at index 1"
}
```

## 3. isEmail(email, [message], [statusCode])

What it does: Checks if something looks like an email (e.g., "name@site.com").

Syntax:
email: The email you’re checking.
message (optional): Error message if it’s wrong (default: "Invalid email format").
statusCode (optional): Error number (default: 400).

Returns: true if it’s an email, or throws an error if not.

Example
```javascript 
const { isEmail } = require("node-easyvalid");

try {
  isEmail("me@example.com", "That’s not an email!"); // Returns true
  isEmail("not-an-email", "That’s not an email!"); // Throws "That’s not an email!"
} catch (error) {
  console.log(error.message); // "That’s not an email!"
}
```
## 4. minLength(value, min, [message], [statusCode])

What it does: Makes sure text is long enough (like a password).

Syntax:
value: The text to check.
min: The smallest length allowed (a number).
message (optional): Error message if too short (default: "Must be at least {min} characters").
statusCode (optional): Error number (default: 400).

Returns: true if long enough, or throws an error if not.

Example

```javascript
const { minLength } = require("node-easyvalid");

try {
  minLength("password123", 8, "Password too short!"); // Returns true
  minLength("pass", 8, "Password too short!"); // Throws "Password too short!"
} catch (error) {
  console.log(error.message); // "Password too short!"
}
```
## 5. isNumber(value, [message], [statusCode])

What it does: Checks if something is a number (like 42 or "42").

Syntax:
value: The thing to check.
message (optional): Error message if it’s not a number (default: "Must be a number").
statusCode (optional): Error number (default: 400).

Returns: true if it’s a number, or throws an error if not.

Example

```javascript
const { isNumber } = require("node-easyvalid");

try {
  isNumber(25, "Age must be a number!"); // Returns true
  isNumber("25", "Age must be a number!"); // Returns true
  isNumber("twenty", "Age must be a number!"); // Throws "Age must be a number!"
} catch (error) {
  console.log(error.message); // "Age must be a number!"
}
```


# Real-World Use Cases
## 1. Express API - User Registration
Validate user inputs in an Express API for registration:

```javascript
const { isTrue, isEmail, minLength, isNumber } = require("node-easyvalid");

// Registration endpoint
app.post("/api/register", (req, res, next) => {
    try {
        const { username, email, password, age } = req.body;

        // Validate inputs
        isTrue(username, "Username is required",400);
        minLength(username, 3, "Username must be at least 3 characters");
        isEmail(email, "Please provide a valid email");
        minLength(password, 8, "Password must be at least 8 characters");
        isNumber(age, "Age must be a number");

        // Simulate successful registration
        res.status(201).json({
            message: "User registered successfully",
            user: { username, email, age },
        });
    } catch (error) {
        res.status(error.statusCode || 500).json({ message: error.message || "Internal Server Error" });
    }
});
```

# Questions?
## If you’re stuck, feel free to ask! You can email ameenmohammedak@gmail.com