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# Date and Time
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Comprehensive date validation including relative time checks, specific date matching, and time range validation.
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## Capabilities
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### Relative Time Checks
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#### Today Check
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Checks if the given date represents today.
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```javascript { .api }
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/**
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 * Checks if the given date object indicates today
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 * @param date - Date object to check
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 * @returns True if date is today
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 * Interfaces: not, all, any
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 */
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function today(date: Date): boolean;
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```
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**Usage Example:**
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```javascript
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const today = new Date();
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is.today(today);            // true
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const yesterday = new Date(new Date().setDate(new Date().getDate() - 1));
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is.today(yesterday);        // false
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is.not.today(yesterday);    // true
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is.all.today(today, today); // true
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is.any.today(today, yesterday); // true
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```
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#### Yesterday Check
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Checks if the given date represents yesterday.
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```javascript { .api }
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/**
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 * Checks if the given date object indicates yesterday
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 * @param date - Date object to check
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 * @returns True if date is yesterday
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 * Interfaces: not, all, any
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 */
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function yesterday(date: Date): boolean;
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```
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**Usage Example:**
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```javascript
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const today = new Date();
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const yesterday = new Date(new Date().setDate(new Date().getDate() - 1));
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is.yesterday(yesterday);    // true
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is.yesterday(today);        // false
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is.not.yesterday(today);    // true
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```
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#### Tomorrow Check
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Checks if the given date represents tomorrow.
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```javascript { .api }
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/**
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 * Checks if the given date object indicates tomorrow
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 * @param date - Date object to check
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 * @returns True if date is tomorrow
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 * Interfaces: not, all, any
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 */
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function tomorrow(date: Date): boolean;
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```
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**Usage Example:**
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```javascript
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const today = new Date();
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const tomorrow = new Date(new Date().setDate(new Date().getDate() + 1));
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is.tomorrow(tomorrow);      // true
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is.tomorrow(today);         // false
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is.not.tomorrow(today);     // true
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```
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#### Past and Future Checks
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Checks if the given date is in the past or future.
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```javascript { .api }
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/**
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 * Checks if the given date object indicates past
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 * @param date - Date object to check
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 * @returns True if date is in the past
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 * Interfaces: not, all, any
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 */
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function past(date: Date): boolean;
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/**
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 * Checks if the given date object indicates future
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 * @param date - Date object to check
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 * @returns True if date is in the future
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 * Interfaces: not, all, any
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 */
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function future(date: Date): boolean;
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```
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**Usage Example:**
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```javascript
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const yesterday = new Date(new Date().setDate(new Date().getDate() - 1));
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const tomorrow = new Date(new Date().setDate(new Date().getDate() + 1));
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is.past(yesterday);         // true
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is.future(tomorrow);        // true
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is.not.past(tomorrow);      // true
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is.not.future(yesterday);   // true
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```
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### Specific Date Matching
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#### Day Check
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Checks if the given date matches a specific day of the week.
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```javascript { .api }
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/**
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 * Checks if the given date objects' day equals given dayString parameter
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 * @param date - Date object to check
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 * @param day - Day name (lowercase: 'monday', 'tuesday', etc.)
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 * @returns True if date falls on the specified day
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 * Interfaces: not
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 */
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function day(date: Date, day: string): boolean;
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```
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**Usage Example:**
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```javascript
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const mondayObj = new Date('01/26/2015');
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is.day(mondayObj, 'monday');    // true
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is.day(mondayObj, 'tuesday');   // false
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is.not.day(mondayObj, 'tuesday'); // true
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```
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#### Month Check
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Checks if the given date matches a specific month.
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```javascript { .api }
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/**
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 * Checks if the given date objects' month equals given monthString parameter
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 * @param date - Date object to check
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 * @param month - Month name (lowercase: 'january', 'february', etc.)
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 * @returns True if date falls in the specified month
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 * Interfaces: not
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 */
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function month(date: Date, month: string): boolean;
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```
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**Usage Example:**
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```javascript
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const januaryObj = new Date('01/26/2015');
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is.month(januaryObj, 'january'); // true
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is.month(januaryObj, 'february'); // false
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is.not.month(januaryObj, 'february'); // true
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```
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#### Year Check
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Checks if the given date matches a specific year.
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```javascript { .api }
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/**
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 * Checks if the given date objects' year equals given yearNumber parameter
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 * @param date - Date object to check
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 * @param year - Year number
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 * @returns True if date falls in the specified year
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 * Interfaces: not
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 */
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function year(date: Date, year: number): boolean;
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```
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**Usage Example:**
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```javascript
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const year2015 = new Date('01/26/2015');
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is.year(year2015, 2015);    // true
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is.year(year2015, 2016);    // false
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is.not.year(year2015, 2016); // true
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```
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### Time Range Validation
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#### Date Range Check
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Checks if a date falls within a specified range.
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```javascript { .api }
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/**
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 * Checks if date is within given range
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 * @param date - Date to check
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 * @param start - Start date of range
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 * @param end - End date of range
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 * @returns True if date is between start and end dates
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 * Interfaces: not
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 */
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function inDateRange(date: Date, start: Date, end: Date): boolean;
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```
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**Usage Example:**
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```javascript
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const saturday = new Date('01/24/2015');
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const sunday = new Date('01/25/2015');
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const monday = new Date('01/26/2015');
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is.inDateRange(sunday, saturday, monday); // true
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is.inDateRange(saturday, sunday, monday); // false
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is.not.inDateRange(saturday, sunday, monday); // true
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```
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#### Relative Range Checks
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Checks if dates fall within relative time periods.
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```javascript { .api }
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/**
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 * Checks if the given date is between now and 7 days ago
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 * @param date - Date to check
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 * @returns True if date is in last week
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 * Interfaces: not, all, any
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 */
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function inLastWeek(date: Date): boolean;
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/**
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 * Checks if the given date is between now and a month ago
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 * @param date - Date to check
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 * @returns True if date is in last month
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 * Interfaces: not, all, any
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 */
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function inLastMonth(date: Date): boolean;
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/**
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 * Checks if the given date is between now and a year ago
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 * @param date - Date to check
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 * @returns True if date is in last year
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 * Interfaces: not, all, any
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 */
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function inLastYear(date: Date): boolean;
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/**
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 * Checks if the given date is between now and 7 days later
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 * @param date - Date to check
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 * @returns True if date is in next week
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 * Interfaces: not, all, any
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 */
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function inNextWeek(date: Date): boolean;
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/**
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 * Checks if the given date is between now and a month later
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 * @param date - Date to check
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 * @returns True if date is in next month
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 * Interfaces: not, all, any
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 */
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function inNextMonth(date: Date): boolean;
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/**
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 * Checks if the given date is between now and a year later
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 * @param date - Date to check
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 * @returns True if date is in next year
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 * Interfaces: not, all, any
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 */
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function inNextYear(date: Date): boolean;
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```
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### Weekend and Weekday Checks
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Checks if dates fall on weekends or weekdays.
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```javascript { .api }
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/**
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 * Checks if the given date objects' day is weekend
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 * @param date - Date to check
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 * @returns True if date is Saturday or Sunday
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 * Interfaces: not, all, any
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 */
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function weekend(date: Date): boolean;
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/**
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 * Checks if the given date objects' day is weekday
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 * @param date - Date to check
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 * @returns True if date is Monday through Friday
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 * Interfaces: not, all, any
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 */
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function weekday(date: Date): boolean;
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```
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**Usage Example:**
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```javascript
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const monday = new Date('01/26/2015');
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const sunday = new Date('01/25/2015');
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is.weekend(sunday);         // true
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is.weekday(monday);         // true
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is.not.weekend(monday);     // true
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is.not.weekday(sunday);     // true
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```
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### Special Date Checks
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#### Leap Year Check
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Checks if the given year is a leap year.
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```javascript { .api }
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/**
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 * Checks if the given year number is a leap year
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 * @param year - Year number to check
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 * @returns True if year is a leap year
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 * Interfaces: not, all, any
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 */
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function leapYear(year: number): boolean;
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```
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**Usage Example:**
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```javascript
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is.leapYear(2016);          // true
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is.leapYear(2015);          // false
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is.not.leapYear(2015);      // true
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is.all.leapYear(2016, 2020); // true
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is.any.leapYear(2015, 2016); // true
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```
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#### Quarter Check
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Checks if the given date falls in a specific quarter.
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```javascript { .api }
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/**
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 * Checks if the given date is in the parameter quarter
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 * @param date - Date to check
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 * @param quarter - Quarter number (1-4)
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 * @returns True if date falls in specified quarter
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 * Interfaces: not
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 */
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function quarterOfYear(date: Date, quarter: number): boolean;
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```
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**Usage Example:**
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```javascript
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const firstQuarter = new Date('01/26/2015');
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const secondQuarter = new Date('05/26/2015');
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is.quarterOfYear(firstQuarter, 1);  // true
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is.quarterOfYear(secondQuarter, 1); // false
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is.not.quarterOfYear(secondQuarter, 1); // true
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```
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#### Daylight Saving Time Check
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Checks if the given date is in daylight saving time.
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```javascript { .api }
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/**
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 * Checks if the given date is in daylight saving time
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 * @param date - Date to check
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 * @returns True if date is in daylight saving time
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 * Interfaces: not, all, any
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 */
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function dayLightSavingTime(date: Date): boolean;
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```
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**Usage Example:**
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```javascript
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// For Turkey Time Zone
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const january1 = new Date('01/01/2015');
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const june1 = new Date('06/01/2015');
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is.dayLightSavingTime(june1);    // true
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is.dayLightSavingTime(january1); // false
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is.not.dayLightSavingTime(january1); // true
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```