freeCodeCamp/curriculum/challenges/english/25-front-end-development/lab-leap-year-calculator/66c06fad3475cd92421b9ac2.md

id, title, challengeType, dashedName

id	title	challengeType	dashedName
66c06fad3475cd92421b9ac2	Build a Leap Year Calculator	25	build-a-leap-year-calculator

--description--

A leap year is a year that is divisible by 4, except for years that are divisible by 100 and not divisible by 400. For example, 2000 is a leap year, but 1900 is not. Also, a leap year has an extra day in February, which is the 29th day of the month.

Fulfill the user stories below and get all the tests to pass to complete the lab.

User Stories:

1. Define a function called isLeapYear that takes a number as an argument.

2. Outside the function, declare a variable year that stores the value of the year you want to check.

3. Inside the function, use an if/ else statement or a ternary operator to check if the year is a leap year.

4. To check if the year is a leap year, fulfill the following conditions:

   • If the year is divisible by 4, then it is a leap year.
   • Unless the year is also divisible by 100, then it is not a leap year.
   • Unless the year is also divisible by 400, then it is a leap year.

5. If the year is a leap year, return [year] is a leap year.. Otherwise, return [year] is not a leap year.. You will replace [year] with the parameter defined in the isLeapYear function.

6. You should call the isLeapYear function with year as the argument and assign the result to a variable named result.

7. You should output the result variable to the console using console.log().

--hints--

You should define a function named isLeapYear.

assert.isFunction(isLeapYear);

The isLeapYear function should take a number as an argument.

assert.match(isLeapYear.toString(), /\s*isLeapYear\(\s*\w+\s*\)/);

You should declare a variable year and assign it a value to check if it is a leap year.

assert.isDefined(year);

The year variable shouldn't be empty.

assert.isNotNull(year);

With 2024 as the value of the year variable, the result should be 2024 is a leap year..

assert.strictEqual(isLeapYear(2024), '2024 is a leap year.');

With 2000 as the value of the year variable, the result should be 2000 is a leap year..

assert.strictEqual(isLeapYear(2000), '2000 is a leap year.');

With 1900 as the value of the year variable, the result should be 1900 is not a leap year..

assert.strictEqual(isLeapYear(1900), '1900 is not a leap year.');

You should call the isLeapYear function and pass year as a parameter.

assert.match(__helpers.removeJSComments(code), /isLeapYear\(\s*year\s*\)/);

You should store the result of calling the isLeapYear function in a variable named result.

assert.match(__helpers.removeJSComments(code), /(?:var|let|const)\s+result\s*=\s*isLeapYear\(\s*year\s*\)/);

You should output the result to the console using console.log().

assert.match(__helpers.removeJSComments(code), /console\.log\(\s*result\s*\)/);

--seed--

--seed-contents--

--solutions--

function isLeapYear(year) {
  if ((year % 4 === 0 && year % 100 !== 0) || year % 400 === 0) {
    return(year + " is a leap year.");
  } else {
    return(year + " is not a leap year.");
  }
}

const year = 2024;
const result = isLeapYear(year);
console.log(result);