freeCodeCamp/curriculum/challenges/english/10-coding-interview-prep/rosetta-code/leap-year.md

id	title	challengeType	forumTopicId
5a23c84252665b21eecc7ede	Leap year	5	302300

Description

Determine whether a given year is a leap year in the Gregorian calendar.

Instructions

Tests

tests:
  - text: <code>isLeapYear</code> should be a function.
    testString: assert(typeof isLeapYear == 'function');
  - text: <code>isLeapYear()</code> should return a boolean.
    testString: assert(typeof isLeapYear(2018) == 'boolean');
  - text: <code>isLeapYear(2018)</code> should return <code>false</code>.
    testString: assert.equal(isLeapYear(2018), false);
  - text: <code>isLeapYear(2016)</code> should return <code>true</code>.
    testString: assert.equal(isLeapYear(2016), true);
  - text: <code>isLeapYear(2000)</code> should return <code>true</code>.
    testString: assert.equal(isLeapYear(2000), true);
  - text: <code>isLeapYear(1900)</code> should return <code>false</code>.
    testString: assert.equal(isLeapYear(1900), false);
  - text: <code>isLeapYear(1996)</code> should return <code>true</code>.
    testString: assert.equal(isLeapYear(1996), true);
  - text: <code>isLeapYear(1800)</code> should return <code>false</code>.
    testString: assert.equal(isLeapYear(1800), false);

Challenge Seed

function isLeapYear(year) {

}

Solution

function isLeapYear(year) {
  return year % 100 === 0 ? year % 400 === 0 : year % 4 === 0;
}