Leap-year-checker NPM

leap-year-checker

Returns true if the value is leap year. A simple JavaScript function to check if a given year is a leap year. This function includes error handling to validate the input.

Installation

npm install leap-year-checker

Usage

const { isLeapYear, getLeapYears, getNextLeapYear, getPreviousLeapYear } = require("leap-year-checker");

try {
  // Check if a year is a leap year
  console.log(isLeapYear(2024)); // Expected output: true
  console.log(isLeapYear(2023)); // Expected output: false

  // Find leap years within a range
  console.log(getLeapYears(2000, 2024)); // Expected output: [2000, 2004, 2008, 2012, 2016, 2020, 2024]

  // Get the next leap year after a given year
  console.log(getNextLeapYear(2023)); // Expected output: 2024

  // Get the previous leap year before a given year
  console.log(getPreviousLeapYear(2024)); // Expected output: 2020

  // Error handling for invalid inputs
  console.log(isLeapYear("2024")); // Throws error: Invalid input: year must be a positive integer.
  
} catch (error) {
  console.error("Error:", error.message);
}

Function Implementation

/**
 * Checks if a provided year is a leap year.
 * @param {number} year - The year to check
 * @throws {Error} - Throws an error if the input is not a valid positive integer
 * @returns {boolean} - Returns true if the year is a leap year, false otherwise
 */
function isLeapYear(year) {
  // Error handling: Check if input is a valid number and an integer
  if (typeof year !== 'number' || !Number.isInteger(year) || year <= 0) {
    throw new Error("Invalid input: year must be a positive integer.");
  }

  // Return true if it's a leap year, false otherwise
  return (year % 4 === 0 && year % 100 !== 0) || (year % 400 === 0);
}