102 lines
4.0 KiB
Markdown
102 lines
4.0 KiB
Markdown
---
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title: Date manipulation
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id: 5966c21cf732a95f1b67dd28
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challengeType: 5
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---
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## Description
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<section id='description'>
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Task:
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<p>Given a date string in EST, output the given date as a string with 12 hours added to the time. </p>
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<p>Time zone should be preserved.</p>
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<p>Example input: </p>
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<p><code>"March 7 2009 7:30pm EST"</code></p>
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<p>Example output: </p>
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<p><code>"March 8 2009 7:30am EST"</code></p>
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</section>
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## Instructions
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<section id='instructions'>
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</section>
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## Tests
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<section id='tests'>
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```yml
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tests:
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- text: <code>add12Hours</code> is a function.
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testString: assert(typeof add12Hours === 'function', '<code>add12Hours</code> is a function.');
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- text: <code>add12Hours(dateString)</code> should return a string.
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testString: assert(typeof add12Hours('January 17 2017 11:43am EST') === 'string', '<code>add12Hours(dateString)</code> should return a string.');
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- text: <code>add12Hours("January 17 2017 11:43am EST")</code> should return <code>"January 17 2017 11:43pm EST"</code>
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testString: assert(add12Hours('January 17 2017 11:43am EST') === 'January 17 2017 11:43pm EST', '<code>add12Hours("January 17 2017 11:43am EST")</code> should return <code>"January 17 2017 11:43pm EST"</code>');
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- text: Should handel day change. <code>add12Hours("March 7 2009 7:30pm EST")</code> should return <code>"March 8 2009 7:30am EST"</code>
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testString: assert(add12Hours('March 7 2009 7:30pm EST') === 'March 8 2009 7:30am EST', 'Should handel day change. <code>add12Hours("March 7 2009 7:30pm EST")</code> should return <code>"March 8 2009 7:30am EST"</code>');
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- text: Should handel month change in a leap years. <code>add12Hours("February 29 2004 9:15pm EST")</code> should return <code>"March 1 2004 9:15am EST"</code>
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testString: assert(add12Hours('February 29 2004 9:15pm EST') === 'March 1 2004 9:15am EST', 'Should handel month change in a leap years. <code>add12Hours("February 29 2004 9:15pm EST")</code> should return <code>"March 1 2004 9:15am EST"</code>');
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- text: Should handel month change in a common years. <code>add12Hours("February 28 1999 3:15pm EST")</code> should return <code>"March 1 1999 3:15am EST"</code>
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testString: assert(add12Hours('February 28 1999 3:15pm EST') === 'March 1 1999 3:15am EST', 'Should handel month change in a common years. <code>add12Hours("February 28 1999 3:15pm EST")</code> should return <code>"March 1 1999 3:15am EST"</code>');
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- text: Should handel year change. <code>add12Hours("December 31 2020 1:45pm EST")</code> should return <code>"January 1 2021 1:45am EST"</code>
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testString: assert(add12Hours('December 31 2020 1:45pm EST') === 'January 1 2021 1:45am EST', 'Should handel year change. <code>add12Hours("December 31 2020 1:45pm EST")</code> should return <code>"January 1 2021 1:45am EST"</code>');
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```
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</section>
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## Challenge Seed
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<section id='challengeSeed'>
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<div id='js-seed'>
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```js
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function add12Hours (dateString) {
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// Good luck!
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return true;
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}
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```
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</div>
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</section>
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## Solution
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<section id='solution'>
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```js
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function add12Hours (dateString) {
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const months = ['January', 'February', 'March', 'April', 'May', 'June',
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'July', 'August', 'September', 'October', 'November', 'December'];
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// Get the parts of the string
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const parts = dateString.split(' ');
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const month = months.indexOf(parts[0]);
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const day = parseInt(parts[1], 10);
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const year = parseInt(parts[2], 10);
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const time = parts[3].split(':');
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let hours = parseInt(time[0], 10);
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if (time[1].slice(-2) === 'pm') {
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hours += 12;
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}
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const minutes = parseInt(time[1].slice(0, -2), 10);
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// Create a date with given parts, and updated hours
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const date = new Date();
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date.setFullYear(year, month, day);
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date.setHours(hours + 12); // Add 12 hours
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date.setMinutes(minutes);
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let hoursOutput = date.getHours();
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let abbreviation = 'am';
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if (hoursOutput > 12) {
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hoursOutput -= 12;
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abbreviation = 'pm';
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}
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return `${months[date.getMonth()]} ${date.getDate()} ${date.getFullYear()} ${hoursOutput}:${date.getMinutes()}${abbreviation} EST`;
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}
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```
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</section>
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