README.md for validate.js

validate.js provides a utility function for validating arguments in JavaScript.

Installation:

This library is not intended for external installation. It’s meant to be included directly in your project.

Usage:

The validate.js library exports a single function named validate. This function takes three arguments:

  1. value (required): The value to be validated.
  2. types (optional): An array of valid types for the value.
  3. validValues (optional): An array of valid values for the value (if applicable).

Example:

import { validate } from './validate.js';

// Validate a string value
const name = "John Doe";
validate(name, ["string"]); 

// Validate an integer within a range
const age = 25;
validate(age, ["number"], [18, 25, 30]);

// Validate an object with specific properties
const user = { name: "Alice", age: 30 };
const userTypes = { name: "string", age: "number" };
validate(user, [userTypes]);

// Handle errors (optional)
try {
  validate(123, ["string"]); // This will throw a TypeError
} catch (error) {
  console.error(error.message);
}

Function Behavior:

  • If no arguments are provided, the function throws a TypeError indicating that at least one argument (the value to validate) is required.
  • If only the value is provided, the function simply returns true, assuming no type or value restrictions are specified.
  • If the second argument (types) is provided:
    • It must be an array.
    • If the array is empty, all types are considered valid (no type checking).
    • If the array contains types, the function checks if the value’s type matches any of the specified types using instanceof for functions and deep object comparison for objects.
    • If a type mismatch occurs, the function throws a TypeError with a descriptive message.
  • If the third argument (validValues) is provided:
    • It must be an array.
    • The function checks if the value exists within the validValues array using the includes method.
    • If the value is not found in the valid values list, the function throws a TypeError with a message indicating the expected valid values.

Additional Notes:

  • This implementation performs basic type and value validation. For more complex validation scenarios, consider using dedicated validation libraries.
  • The deep object comparison is a simplified approach. You might need to customize it for specific object validation needs.

Contributing:

This is a basic example. Feel free to modify and extend the functionality based on your specific requirements.