> For the complete documentation index, see [llms.txt](https://osl.mistium.com/llms.txt). Markdown versions of documentation pages are available by appending `.md` to page URLs; this page is available as [Markdown](https://osl.mistium.com/packages/mathtime/date.md).

# date

> Dates, durations and time zones

Use `date` for current time, Unix timestamps, durations, time-zone conversion, formatting, and date arithmetic.

```javascript
import "osl/date"
```

## API reference

### `date`

| Method                                          | Returns        | Description                       |
| ----------------------------------------------- | -------------- | --------------------------------- |
| `date.now()`                                    | `dateDateTime` | Returns current date/time.        |
| `date.fromUnix(s: number)`                      | `dateDateTime` | Creates from unix.                |
| `date.fromUnixMs(ms: number)`                   | `dateDateTime` | Creates from unix ms.             |
| `date.duration(value: number)`                  | `dateDuration` | Runs the duration operation.      |
| `date.isLeap(year: number)`                     | `boolean`      | Reports whether leap.             |
| `date.daysInMonth(year: number, month: number)` | `number`       | Runs the days in month operation. |

### `dateDateTime` values

Methods available on `dateDateTime` values returned by this package or constructed by the language.

| Method                                        | Returns             | Description                     |
| --------------------------------------------- | ------------------- | ------------------------------- |
| `value.unix()`                                | `number`            | Runs the unix operation.        |
| `value.unixMs()`                              | `number`            | Runs the unix ms operation.     |
| `value.iso()`                                 | `string`            | Runs the iso operation.         |
| `value.format(layout: string)`                | `string`            | Formats a value for display.    |
| `value.add(unit: string, value: number)`      | `dateDateTime`      | Runs the add operation.         |
| `value.subtract(unit: string, value: number)` | `dateDateTime`      | Runs the subtract operation.    |
| `value.addDuration(v: dateDuration)`          | `dateDateTime`      | Adds duration.                  |
| `value.since(other: dateDateTime)`            | `dateDuration`      | Runs the since operation.       |
| `value.until(other: dateDateTime)`            | `dateDuration`      | Runs the until operation.       |
| `value.with(field: string, value: number)`    | `dateDateTime`      | Runs the with operation.        |
| `value.round(unit: string)`                   | `dateDateTime`      | Runs the round operation.       |
| `value.inTimezone(tz: string)`                | `dateZonedDateTime` | Runs the in timezone operation. |
| `value.compare(other: dateDateTime)`          | `number`            | Runs the compare operation.     |
| `value.equals(other: dateDateTime)`           | `boolean`           | Runs the equals operation.      |
| `value.before(other: dateDateTime)`           | `boolean`           | Runs the before operation.      |
| `value.after(other: dateDateTime)`            | `boolean`           | Runs the after operation.       |

### `dateDuration` values

Methods available on `dateDuration` values returned by this package or constructed by the language.

| Method                      | Returns  | Description                            |
| --------------------------- | -------- | -------------------------------------- |
| `value.totalMilliseconds()` | `number` | Runs the total milliseconds operation. |
| `value.seconds()`           | `number` | Runs the seconds operation.            |
| `value.minutes()`           | `number` | Runs the minutes operation.            |
| `value.hours()`             | `number` | Runs the hours operation.              |
| `value.days()`              | `number` | Runs the days operation.               |

### `dateZonedDateTime` values

Methods available on `dateZonedDateTime` values returned by this package or constructed by the language.

| Method                         | Returns  | Description                  |
| ------------------------------ | -------- | ---------------------------- |
| `value.iso()`                  | `string` | Runs the iso operation.      |
| `value.format(layout: string)` | `string` | Formats a value for display. |

## Notes

* Standard-library imports accept both `import "osl/date"` and `import "date"`.
* Return values such as `array` and `object` are regular OSL values unless a returned object section says otherwise.