freeCodeCamp/curriculum/challenges/english/08-coding-interview-prep/rosetta-code/convert-seconds-to-compound-duration.english.md

---
title: Convert seconds to compound duration
id: 596fd036dc1ab896c5db98b1
challengeType: 5
---

## Description
<section id='description'>
Implement a function which:
<ul>
  <li>takes a positive integer representing a duration in seconds as input (e.g., <code>100</code>), and</li>
  <li>returns a string which shows the same duration decomposed into weeks, days, hours, minutes, and seconds as detailed below (e.g., <code>1 min, 40 sec</code>).</li>
</ul>
Demonstrate that it passes the following three test-cases:
<div style="font-size:115%; font-weight: bold;">Test Cases</div>
<table>
  <tbody>
    <tr>
      <th>input number</th>
      <th>output number</th>
    </tr>
    <tr>
      <td>7259</td>
      <td><code>2 hr, 59 sec</code></td>
    </tr>
    <tr>
      <td>86400</td>
      <td><code>1 d</code></td>
    </tr>
    <tr>
      <td>6000000</td>
      <td><code>9 wk, 6 d, 10 hr, 40 min</code></td>
    </tr>
  </tbody>
</table>
<div style="font-size:115%; font-weight: bold;">Details</div>
<ul>
  <li>
    The following five units should be used:
    <table>
      <tbody>
        <tr>
          <th>unit</th>
          <th>suffix used in output</th>
          <th>conversion</th>
        </tr>
        <tr>
          <td>week</td>
          <td><code>wk</code></td>
          <td>1 week = 7 days</td>
        </tr>
        <tr>
          <td>day</td>
          <td><code>d</code></td>
          <td>1 day = 24 hours</td>
        </tr>
        <tr>
          <td>hour</td>
          <td><code>hr</code></td>
          <td>1 hour = 60 minutes</td>
        </tr>
        <tr>
          <td>minute</td>
          <td><code>min</code></td>
          <td>1 minute = 60 seconds</td>
        </tr>
        <tr>
          <td>second</td>
          <td><code>sec</code></td>
          <td></td>
        </tr>
      </tbody>
    </table>
  </li>
  <li>
    However, <b>only</b> include quantities with non-zero values in the output (e.g., return <code>1 d</code> and not <code>0 wk, 1 d, 0 hr, 0 min, 0 sec</code>).
  </li>
  <li>
    Give larger units precedence over smaller ones as much as possible (e.g., return <code>2 min, 10 sec</code> and not <code>1 min, 70 sec</code> or <code>130 sec</code>).
  </li>
  <li>
    Mimic the formatting shown in the test-cases (quantities sorted from largest unit to smallest and separated by comma+space; value and unit of each quantity separated by space).
  </li>
</ul>
</section>

## Instructions
<section id='instructions'>

</section>

## Tests
<section id='tests'>

```yml
tests:
  - text: <code>convertSeconds</code> is a function.
    testString: assert(typeof convertSeconds === 'function', '<code>convertSeconds</code> is a function.');
  - text: <code>convertSeconds(7259)</code> should return <code>2 hr, 59 sec</code>.
    testString: assert.equal(convertSeconds(testCases[0]), results[0], '<code>convertSeconds(7259)</code> should return <code>2 hr, 59 sec</code>.');
  - text: <code>convertSeconds(86400)</code> should return <code>1 d</code>.
    testString: assert.equal(convertSeconds(testCases[1]), results[1], '<code>convertSeconds(86400)</code> should return <code>1 d</code>.');
  - text: <code>convertSeconds(6000000)</code> should return <code>9 wk, 6 d, 10 hr, 40 min</code>.
    testString: assert.equal(convertSeconds(testCases[2]), results[2], '<code>convertSeconds(6000000)</code> should return <code>9 wk, 6 d, 10 hr, 40 min</code>.');

```

</section>

## Challenge Seed
<section id='challengeSeed'>

<div id='js-seed'>

```js
function convertSeconds (sec) {
  // Good luck!
  return true;
}
```

</div>


### After Test
<div id='js-teardown'>

```js
const testCases = [7259, 86400, 6000000];
const results = ['2 hr, 59 sec', '1 d', '9 wk, 6 d, 10 hr, 40 min'];
```

</div>

</section>

## Solution
<section id='solution'>


```js
function convertSeconds (sec) {
  const localNames = ['wk', 'd', 'hr', 'min', 'sec'];
  // compoundDuration :: [String] -> Int -> String
  const compoundDuration = (labels, intSeconds) =>
    weekParts(intSeconds)
    .map((v, i) => [v, labels[i]])
    .reduce((a, x) =>
      a.concat(x[0] ? [`${x[0]} ${x[1] || '?'}`] : []), []
    )
    .join(', ');

    // weekParts :: Int -> [Int]
  const weekParts = intSeconds => [0, 7, 24, 60, 60]
    .reduceRight((a, x) => {
      const r = a.rem;
      const mod = x !== 0 ? r % x : r;

      return {
        rem: (r - mod) / (x || 1),
        parts: [mod].concat(a.parts)
      };
    }, {
      rem: intSeconds,
      parts: []
    })
    .parts;

  return compoundDuration(localNames, sec);
}

```

</section>