2022-01-20 19:30:18 +00:00
|
|
|
---
|
|
|
|
id: 5966c21cf732a95f1b67dd28
|
2022-01-22 15:08:20 +00:00
|
|
|
title: 日付操作
|
2022-01-20 19:30:18 +00:00
|
|
|
challengeType: 5
|
|
|
|
forumTopicId: 302244
|
|
|
|
dashedName: date-manipulation
|
|
|
|
---
|
|
|
|
|
|
|
|
# --description--
|
|
|
|
|
2022-01-22 15:08:20 +00:00
|
|
|
ESTに基づく日付文字列が与えられると、12時間を加えて日付を文字列として出力します。 タイムゾーンは保持します。
|
2022-01-20 19:30:18 +00:00
|
|
|
|
2022-01-22 15:08:20 +00:00
|
|
|
入力例: `"March 6 2009 7:30pm EST"`
|
2022-01-20 19:30:18 +00:00
|
|
|
|
2022-01-22 15:08:20 +00:00
|
|
|
出力例: `"March 7 2009 7:30am EST"`
|
2022-01-20 19:30:18 +00:00
|
|
|
|
|
|
|
# --hints--
|
|
|
|
|
2022-01-22 15:08:20 +00:00
|
|
|
`add12Hours` という関数です。
|
2022-01-20 19:30:18 +00:00
|
|
|
|
|
|
|
```js
|
|
|
|
assert(typeof add12Hours === 'function');
|
|
|
|
```
|
|
|
|
|
2022-01-22 15:08:20 +00:00
|
|
|
`add12Hours(dateString)` は文字列を返します。
|
2022-01-20 19:30:18 +00:00
|
|
|
|
|
|
|
```js
|
|
|
|
assert(typeof add12Hours('January 17 2017 11:43am EST') === 'string');
|
|
|
|
```
|
|
|
|
|
2022-01-22 15:08:20 +00:00
|
|
|
`add12Hours("January 17 2017 11:43am EST")` は `"January 17 2017 11:43pm EST"` を返します。
|
2022-01-20 19:30:18 +00:00
|
|
|
|
|
|
|
```js
|
|
|
|
assert(
|
|
|
|
add12Hours('January 17 2017 11:43am EST') === 'January 17 2017 11:43pm EST'
|
|
|
|
);
|
|
|
|
```
|
|
|
|
|
2022-01-22 15:08:20 +00:00
|
|
|
日付が変更されます。 `add12Hours("March 6 2009 7:30pm EST")` は `"March 7 2009 7:30am EST"` を返します。
|
2022-01-20 19:30:18 +00:00
|
|
|
|
|
|
|
```js
|
|
|
|
assert(add12Hours('March 6 2009 7:30pm EST') === 'March 7 2009 7:30am EST');
|
|
|
|
```
|
|
|
|
|
2022-01-22 15:08:20 +00:00
|
|
|
うるう年の月に変更が加えられます。 `add12Hours("February 29 2004 9:15pm EST")` は `"March 1 2004 9:15am EST"` を返します。
|
2022-01-20 19:30:18 +00:00
|
|
|
|
|
|
|
```js
|
|
|
|
assert(add12Hours('February 29 2004 9:15pm EST') === 'March 1 2004 9:15am EST');
|
|
|
|
```
|
|
|
|
|
2022-01-22 15:08:20 +00:00
|
|
|
平年の月に変更が加えられます。 `add12Hours("February 28 1999 3:15pm EST")` は `"March 1 1999 3:15am EST"` を返します。
|
2022-01-20 19:30:18 +00:00
|
|
|
|
|
|
|
```js
|
|
|
|
assert(add12Hours('February 28 1999 3:15pm EST') === 'March 1 1999 3:15am EST');
|
|
|
|
```
|
|
|
|
|
2022-01-22 15:08:20 +00:00
|
|
|
年に変更が加えられます。 `add12Hours("December 31 2020 1:45pm EST")` は `"January 1 2021 1:45am EST"` を返します。
|
2022-01-20 19:30:18 +00:00
|
|
|
|
|
|
|
```js
|
|
|
|
assert(
|
|
|
|
add12Hours('December 31 2020 1:45pm EST') === 'January 1 2021 1:45am EST'
|
|
|
|
);
|
|
|
|
```
|
|
|
|
|
|
|
|
# --seed--
|
|
|
|
|
|
|
|
## --seed-contents--
|
|
|
|
|
|
|
|
```js
|
|
|
|
function add12Hours(dateString) {
|
|
|
|
|
|
|
|
return true;
|
|
|
|
}
|
|
|
|
```
|
|
|
|
|
|
|
|
# --solutions--
|
|
|
|
|
|
|
|
```js
|
|
|
|
function add12Hours(dateString) {
|
|
|
|
const months = ['January', 'February', 'March', 'April', 'May', 'June',
|
|
|
|
'July', 'August', 'September', 'October', 'November', 'December'];
|
|
|
|
// Get the parts of the string
|
|
|
|
const parts = dateString.split(' ');
|
|
|
|
const month = months.indexOf(parts[0]);
|
|
|
|
const day = parseInt(parts[1], 10);
|
|
|
|
const year = parseInt(parts[2], 10);
|
|
|
|
const time = parts[3].split(':');
|
|
|
|
let hours = parseInt(time[0], 10);
|
|
|
|
if (time[1].slice(-2) === 'pm') {
|
|
|
|
hours += 12;
|
|
|
|
}
|
|
|
|
const minutes = parseInt(time[1].slice(0, -2), 10);
|
|
|
|
|
|
|
|
// Create a date with given parts, and updated hours
|
|
|
|
const date = new Date();
|
|
|
|
date.setFullYear(year, month, day);
|
|
|
|
date.setHours(hours + 12); // Add 12 hours
|
|
|
|
date.setMinutes(minutes);
|
|
|
|
|
|
|
|
let hoursOutput = date.getHours();
|
|
|
|
let abbreviation = 'am';
|
|
|
|
if (hoursOutput > 12) {
|
|
|
|
hoursOutput -= 12;
|
|
|
|
abbreviation = 'pm';
|
|
|
|
}
|
|
|
|
|
|
|
|
return `${months[date.getMonth()]} ${date.getDate()} ${date.getFullYear()} ${hoursOutput}:${date.getMinutes()}${abbreviation} EST`;
|
|
|
|
}
|
|
|
|
```
|