This code calculates the total duration of a list of events in minutes, handling cases where end times are missing. It iterates through the events, calculates the duration of each event, and sums them up to provide the total duration in minutes.

Run example

npm run import -- "sum a list of events"

sum a list of events

// sum up events
function sumEvents(events) {
    var total = 0;
    events.forEach(e => {
        if (typeof e.event.end === 'undefined' || typeof e.event.end.dateTime === 'undefined') {
            console.log('ignoring ' + e.event.summary + ' - ' + JSON.stringify(e.event.start));
            return;
        }
        total += new Date(e.event.end.dateTime).getTime()
            - new Date(e.event.start.dateTime).getTime();
        if(isNaN(total)) {
            throw new Error('nan! ' + JSON.stringify(e.event));
        }
    });
    return total / 1000 / 60 / 60;
};
module.exports = sumEvents;

/**
 * Calculates the total duration of events in milliseconds.
 * 
 * @param {Array} events - An array of event objects.
 * @returns {number} Total duration of events in hours.
 */
function sumEvents(events) {
  // Initialize total duration to 0
  let total = 0;
  
  // Check if events array is valid
  if (!Array.isArray(events)) {
    throw new Error('Events must be an array');
  }
  
  // Iterate over each event
  events.forEach((e, index) => {
    // Ensure event has start and end dates
    if (!e.event ||!e.event.start ||!e.event.end) {
      console.log(`Ignoring event #${index} - ${JSON.stringify(e.event)}`);
      return;
    }
    
    // Ensure start and end dates are valid
    if (!e.event.start.dateTime ||!e.event.end.dateTime) {
      console.log(`Ignoring event #${index} - ${JSON.stringify(e.event)}`);
      return;
    }
    
    // Calculate duration
    const duration = new Date(e.event.end.dateTime).getTime() - new Date(e.event.start.dateTime).getTime();
    
    // Check if duration is valid
    if (isNaN(duration)) {
      console.log(`Ignoring event #${index} - ${JSON.stringify(e.event)}`);
      continue;
    }
    
    // Add duration to total
    total += duration;
  });
  
  // Convert total duration from milliseconds to hours
  const hours = total / 1000 / 60 / 60;
  
  // Return total duration
  return hours;
}

module.exports = sumEvents;

This code calculates the total duration of events in minutes.

Here's a breakdown:

1. sumEvents(events) function:

   • Takes an array of events as input, where each event is assumed to have properties like summary, start, and end.

2. Initialization:

   • Initializes a total variable to 0 to store the cumulative duration.

3. Iterating through Events:

   • Uses forEach to loop through each event in the events array.

4. Handling Missing End Times:

   • Checks if the end property exists and if it has a dateTime property. If either is missing, it logs a message and skips the event.

5. Calculating Duration:

   • If both start and end times are present:
     • Creates Date objects from the start.dateTime and end.dateTime strings.
     • Calculates the difference between the two dates in milliseconds.
     • Adds this duration to the total.
     • Includes a check for isNaN(total) to handle potential errors and throw an error if the calculation results in NaN.

6. Returning Total Duration:

   • After processing all events, divides the total milliseconds by 1000 (to get seconds), then by 60 (to get minutes).
   • Returns the total duration in minutes.

7. Export:

   • Exports the sumEvents function for use in other parts of the project.

Let me know if you have any other code snippets you'd like me to explain!