Time Calculator

A simple NPM package to calculate end time based on a start time and duration, or start time based on an end time and duration. This is especially useful for scheduling applications and time management tools.

Installation

To install the package, use the following command:

npm install time-calculator

Usage

Importing the Package

const { calculateEndTime, calculateStartTime } = require('time-calculator');

Functions

calculateEndTime(startTime, duration)

• startTime: A string representing the start time in ISO format.
• duration: A number representing the duration in minutes.

Returns: A string representing the end time in ISO format.

const endTime = calculateEndTime('2024-12-11T10:00:00Z', 120);
console.log(endTime); // '2024-12-11T12:00:00.000Z'

calculateStartTime(endTime, duration)

• endTime: A string representing the end time in ISO format.
• duration: A number representing the duration in minutes.

Returns: A string representing the start time in ISO format.

const startTime = calculateStartTime('2024-12-11T12:00:00Z', 120);
console.log(startTime); // '2024-12-11T10:00:00.000Z'

Use Cases

1. Meeting Scheduling: Automatically calculate the end time of a meeting given its start time and duration, or vice versa.
2. Task Management: Determine when you need to start a task to finish by a specific time.
3. Event Planning: Plan events with precise start and end times.
4. Movie Planning: Calculate the start time if you know the movie duration and the desired end time, ensuring you finish in time for other activities.
5. Scheduling Timers for Electronic Devices: Set timers on devices like kitchen appliances or garden sprinklers by calculating the required start or end time based on the duration of use.

Handling Different Timezones

Example with IST (Indian Standard Time)

Indian Standard Time (IST) is UTC+5:30. You can handle time zones by adjusting the input times accordingly.

Using calculateEndTime in IST

const startTimeIST = new Date('2024-12-11T10:00:00Z').toLocaleString("en-US", {timeZone: "Asia/Kolkata"});
const duration = 120; // 2 hours
const endTimeUTC = calculateEndTime(startTimeIST, duration);

const endTimeIST = new Date(endTimeUTC).toLocaleString("en-US", {timeZone: "Asia/Kolkata"});
console.log('End Time in IST:', endTimeIST);

Using calculateStartTime in IST

const endTimeIST = new Date('2024-12-11T12:00:00Z').toLocaleString("en-US", {timeZone: "Asia/Kolkata"});
const duration = 120; // 2 hours
const startTimeUTC = calculateStartTime(endTimeIST, duration);

const startTimeIST = new Date(startTimeUTC).toLocaleString("en-US", {timeZone: "Asia/Kolkata"});
console.log('Start Time in IST:', startTimeIST);

Running Tests

To run the included tests, use the following command:

npm test

Contributing

Contributions are welcome! Please open an issue or submit a pull request for any improvements or bug fixes.

License

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