freeCodeCamp/curriculum/challenges/english/10-coding-interview-prep/rosetta-code/day-of-the-week.md

---
id: 5966f99c45e8976909a85575
title: Day of the week
challengeType: 5
forumTopicId: 302245
dashedName: day-of-the-week
---

# --description--

A company decides that whenever Xmas falls on a Sunday they will give their workers all extra paid holidays so that, together with any public holidays, workers will not have to work the following week (between the 25th of December and the first of January).

# --instructions--

Write a function that takes a start year and an end year and return an array of all the years where the 25th of December will be a Sunday.

# --hints--

`findXmasSunday` should be a function.

```js
assert(typeof findXmasSunday === 'function');
```

`findXmasSunday(2000, 2100)` should return an array.

```js
assert(typeof findXmasSunday(2000, 2100) === 'object');
```

`findXmasSunday(1970, 2017)` should return `[1977, 1983, 1988, 1994, 2005, 2011, 2016]`

```js
assert.deepEqual(findXmasSunday(1970, 2017), firstSolution);
```

`findXmasSunday(2008, 2121)` should return `[2011, 2016, 2022, 2033, 2039, 2044, 2050, 2061, 2067, 2072, 2078, 2089, 2095, 2101, 2107, 2112, 2118]`

```js
assert.deepEqual(findXmasSunday(2008, 2121), secondSolution);
```

# --seed--

## --after-user-code--

```js
const firstSolution = [1977, 1983, 1988, 1994, 2005, 2011, 2016];
const secondSolution = [2011, 2016, 2022, 2033, 2039, 2044, 2050, 2061, 2067, 2072, 2078, 2089, 2095, 2101, 2107, 2112, 2118];
```

## --seed-contents--

```js
function findXmasSunday(start, end) {

  return true;
}
```

# --solutions--

```js
function findXmasSunday(start, end) {
  const xmasSunday = [];
  for (let year = start; year <= end; year++) {
    const xmas = new Date(year, 11, 25);
    if (xmas.getDay() === 0) {
      xmasSunday.push(year);
    }
  }
  return xmasSunday;
}
```