Insurance Library

A TypeScript library for calculating auto insurance premiums based on various factors including driver age, vehicle age, driving history, and location.

Installation

npm install insurance-lib

Testing

npm test

Usage

import { calculatePremium, InsuranceValidationError } from 'insurance-lib';

try {
  // Calculate premium for a 30-year-old driver with a 2020 vehicle
  const premium = calculatePremium(
    30, // age
    2020, // vehicle year
    0, // accidents in last 5 years
    0, // tickets in last 3 years
    '98115' // zip code
  );

  console.log(`Annual premium: $${premium}`);
} catch (error) {
  if (error instanceof InsuranceValidationError) {
    console.error('Invalid input:', error.message);
    // Handle specific validation errors
    // - InvalidAgeError: Age must be between 16 and 100
    // - InvalidVehicleYearError: Vehicle year must be between 1900 and current year
    // - InvalidZipError: Zip code must be a 5-digit number
    // - TooManyTicketsError: Maximum 5 tickets in last 3 years
    // - TooManyAccidentsError: Maximum 3 accidents in last 5 years
  } else {
    console.error('An unexpected error occurred:', error);
  }
}

Features

• Base premium calculation
• Vehicle age surcharges
• Driver age modifiers
• Violation fees for accidents and tickets
• Location-based multipliers

API

calculatePremium(age: number, vehicleYear: number, accidentsLast5Yrs: number, ticketsLast3Yrs: number, zip: string): number

Calculates the annual premium for an auto insurance policy.

Parameters

• age: The age of the applicant
• vehicleYear: The model year of the vehicle
• accidentsLast5Yrs: Number of accidents in the past 5 years
• ticketsLast3Yrs: Number of tickets in the past 3 years
• zip: Zip code where the vehicle will be located

Returns

The calculated annual premium amount.

Errors

• InsuranceValidationError: Thrown when the input parameters are invalid
  • InvalidAgeError: Age must be between 16 and 100
  • InvalidVehicleYearError: Vehicle year must be between 1900 and current year
  • InvalidZipError: Zip code must be a 5-digit number
  • TooManyTicketsError: Maximum 5 tickets in last 3 years
  • TooManyAccidentsError: Maximum 3 accidents in last 5 years

Design Decisions

• Defined an interface AutoInsuranceApplicant for the applicant to hold the applicant's data
• Implemented base class AutoInsurancePolicy for the insurance policy to allow for future extensibility
• Subclassed the base class with a generic implementation GenericAutoInsurancePolicy to implement the specific logic for the insurance policy based on the requirements
• Used a utility class InsuranceValidator to validate the input parameters
• Added a test suite index.test.ts to validate the functionality of the library and ensure that it is working as expected including edge cases and exception handling

Future Improvements

• Implement different insurance policies with different rules and algorithms for calculating the premium
• Add a database to store the location factors and other related insurance policy data so policies can be modified and extended without changing the code
• Modify the main interface to allow for specifying an insurance policy when calculating the premium
• New APIs for calculating premiums for different types of insurance policies and comparing them
• Extend the applicant interface to allow for more complex applicant profiles
• Persist the applicant data in a database

Contributing

1. Fork the repository
2. Create your feature branch (git checkout -b feature/amazing-feature)
3. Commit your changes (git commit -m 'Add some amazing feature')
4. Push to the branch (git push origin feature/amazing-feature)
5. Open a Pull Request

License

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