@robertocemeri/date-utils/src/date-utils.js

A simple and lightweight JavaScript library for date and time operations with timezone support

class DateUtils {
  constructor(timezone = 'local') {
    this.timezone = timezone;
  }

  // Set timezone
  setTimezone(timezone) {
    this.timezone = timezone;
    return this;
  }

  // Get current date
  currentDate(format = 'YYYY-MM-DD') {
    const date = this._getDateInTimezone();
    return this._formatDate(date, format);
  }

  // Get current year
  currentYear() {
    const date = this._getDateInTimezone();
    return date.getFullYear();
  }

  // Get current time
  currentTime(format = 'HH:mm:ss') {
    const date = this._getDateInTimezone();
    return this._formatTime(date, format);
  }

  // Get current date and time
  currentDateTime(format = 'YYYY-MM-DD HH:mm:ss') {
    const date = this._getDateInTimezone();
    return this._formatDateTime(date, format);
  }

  // Get timestamp
  timestamp() {
    return this._getDateInTimezone().getTime();
  }

  // Private method to get date in specified timezone
  _getDateInTimezone() {
    const now = new Date();
    
    if (this.timezone === 'local' || this.timezone === '') {
      return now;
    }

    if (this.timezone === 'utc') {
      return new Date(now.getTime() + (now.getTimezoneOffset() * 60000));
    }

    // For other timezones, convert using Intl.DateTimeFormat
    try {
      const formatter = new Intl.DateTimeFormat('en-US', {
        timeZone: this.timezone,
        year: 'numeric',
        month: '2-digit',
        day: '2-digit',
        hour: '2-digit',
        minute: '2-digit',
        second: '2-digit',
        hour12: false
      });
      
      const parts = formatter.formatToParts(now);
      const partObject = {};
      parts.forEach(part => {
        partObject[part.type] = part.value;
      });

      return new Date(
        `${partObject.year}-${partObject.month}-${partObject.day}T${partObject.hour}:${partObject.minute}:${partObject.second}`
      );
    } catch (error) {
      console.warn(`Invalid timezone: ${this.timezone}. Using local time.`);
      return now;
    }
  }

  // Private method to format date
  _formatDate(date, format) {
    const year = date.getFullYear();
    const month = String(date.getMonth() + 1).padStart(2, '0');
    const day = String(date.getDate()).padStart(2, '0');

    return format
      .replace('YYYY', year)
      .replace('MM', month)
      .replace('DD', day)
      .replace('YY', String(year).slice(-2))
      .replace('M', date.getMonth() + 1)
      .replace('D', date.getDate());
  }

  // Private method to format time
  _formatTime(date, format) {
    const hours = String(date.getHours()).padStart(2, '0');
    const minutes = String(date.getMinutes()).padStart(2, '0');
    const seconds = String(date.getSeconds()).padStart(2, '0');
    const milliseconds = String(date.getMilliseconds()).padStart(3, '0');

    return format
      .replace('HH', hours)
      .replace('mm', minutes)
      .replace('ss', seconds)
      .replace('SSS', milliseconds)
      .replace('H', date.getHours())
      .replace('m', date.getMinutes())
      .replace('s', date.getSeconds());
  }

  // Private method to format date and time
  _formatDateTime(date, format) {
    const datePart = this._formatDate(date, format);
    return this._formatTime(date, datePart);
  }

  // Utility methods
  static getAvailableTimezones() {
    return Intl.supportedValuesOf('timeZone');
  }

  // Add days to current date
  addDays(days) {
    const date = this._getDateInTimezone();
    date.setDate(date.getDate() + days);
    return new DateUtils(this.timezone)._setCustomDate(date);
  }

  // Subtract days from current date
  subtractDays(days) {
    return this.addDays(-days);
  }

  // For internal use to set custom date
  _setCustomDate(date) {
    this._customDate = date;
    return this;
  }

  // Override _getDateInTimezone for custom dates
  _getDateInTimezone() {
    if (this._customDate) {
      const tempDate = this._customDate;
      this._customDate = null;
      return tempDate;
    }
    
    const now = new Date();
    
    if (this.timezone === 'local' || this.timezone === '') {
      return now;
    }

    if (this.timezone === 'utc') {
      return new Date(now.getTime() + (now.getTimezoneOffset() * 60000));
    }

    try {
      const formatter = new Intl.DateTimeFormat('en-US', {
        timeZone: this.timezone,
        year: 'numeric',
        month: '2-digit',
        day: '2-digit',
        hour: '2-digit',
        minute: '2-digit',
        second: '2-digit',
        hour12: false
      });
      
      const parts = formatter.formatToParts(now);
      const partObject = {};
      parts.forEach(part => {
        partObject[part.type] = part.value;
      });

      return new Date(
        `${partObject.year}-${partObject.month}-${partObject.day}T${partObject.hour}:${partObject.minute}:${partObject.second}`
      );
    } catch (error) {
      console.warn(`Invalid timezone: ${this.timezone}. Using local time.`);
      return now;
    }
  }
}

// Factory function for easy creation
function createDateUtils(timezone = 'local') {
  return new DateUtils(timezone);
}

// Convenience methods
const currentDate = (format) => createDateUtils().currentDate(format);
const currentYear = () => createDateUtils().currentYear();
const currentTime = (format) => createDateUtils().currentTime(format);
const currentDateTime = (format) => createDateUtils().currentDateTime(format);
const timestamp = () => createDateUtils().timestamp();

// Export everything
export {
  DateUtils,
  createDateUtils,
  currentDate,
  currentYear,
  currentTime,
  currentDateTime,
  timestamp
};