110 lines
2.7 KiB
Markdown
110 lines
2.7 KiB
Markdown
---
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id: 5966c21cf732a95f1b67dd28
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title: Date manipulation
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challengeType: 5
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forumTopicId: 302244
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dashedName: date-manipulation
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---
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# --description--
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Given a date string in EST, output the given date as a string with 12 hours added to the time. Time zone should be preserved.
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Example input: `"March 6 2009 7:30pm EST"`
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Example output: `"March 7 2009 7:30am EST"`
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# --hints--
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`add12Hours` should be a function.
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```js
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assert(typeof add12Hours === 'function');
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```
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`add12Hours(dateString)` should return a string.
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```js
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assert(typeof add12Hours('January 17 2017 11:43am EST') === 'string');
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```
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`add12Hours("January 17 2017 11:43am EST")` should return `"January 17 2017 11:43pm EST"`
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```js
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assert(
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add12Hours('January 17 2017 11:43am EST') === 'January 17 2017 11:43pm EST'
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);
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```
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Should handle day change. `add12Hours("March 6 2009 7:30pm EST")` should return `"March 7 2009 7:30am EST"`
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```js
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assert(add12Hours('March 6 2009 7:30pm EST') === 'March 7 2009 7:30am EST');
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```
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Should handle month change in a leap years. `add12Hours("February 29 2004 9:15pm EST")` should return `"March 1 2004 9:15am EST"`
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```js
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assert(add12Hours('February 29 2004 9:15pm EST') === 'March 1 2004 9:15am EST');
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```
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Should handle month change in a common years. `add12Hours("February 28 1999 3:15pm EST")` should return `"March 1 1999 3:15am EST"`
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```js
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assert(add12Hours('February 28 1999 3:15pm EST') === 'March 1 1999 3:15am EST');
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```
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Should handle year change. `add12Hours("December 31 2020 1:45pm EST")` should return `"January 1 2021 1:45am EST"`
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```js
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assert(
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add12Hours('December 31 2020 1:45pm EST') === 'January 1 2021 1:45am EST'
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);
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```
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# --seed--
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## --seed-contents--
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```js
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function add12Hours(dateString) {
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return true;
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}
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```
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# --solutions--
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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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