How to Use Timestamp in iOS Development

Getting Current Timestamp in iOS

Use Date().timeIntervalSince1970 to get the current Unix timestamp in seconds (Double). For milliseconds, multiply by 1000.

let timestamp = Date().timeIntervalSince1970 // Seconds  
let milliseconds = Int64(timestamp * 1000) // Milliseconds  

Converting Timestamp to Date

Use Date(timeIntervalSince1970:) to convert a timestamp back to a Date object.

let date = Date(timeIntervalSince1970: timestamp)  

Formatting Timestamps

Use DateFormatter to display timestamps in a readable format.

let formatter = DateFormatter()  
formatter.dateFormat = "yyyy-MM-dd HH:mm:ss"  
let dateString = formatter.string(from: date)  

For ISO8601 format, use ISO8601DateFormatter:

let isoFormatter = ISO8601DateFormatter()  
let isoString = isoFormatter.string(from: date)  

Timezone Handling

Always work in UTC for consistency, then convert to local time when displaying.

formatter.timeZone = TimeZone(abbreviation: "UTC")  

Storing Timestamps in Core Data

Use Double or Int64 attributes to store timestamps in Core Data.

@NSManaged var timestamp: Double  

Firebase Timestamps

Firebase provides FieldValue.serverTimestamp() for synchronized timestamps.

db.collection("events").document().setData([  
    "timestamp": FieldValue.serverTimestamp()  
])  

Comparing Timestamps

Use Calendar to compare dates accurately.

let calendar = Calendar.current  
let isSameDay = calendar.isDate(date1, inSameDayAs: date2)  

Performance Tips

• Cache DateFormatter instances (they’re expensive to create).
• Use ISO8601DateFormatter for better performance with ISO strings.

Common Issues

• Precision: Unix timestamps are in seconds, but some APIs use milliseconds.
• Timezone: Always verify if the timestamp is UTC or local time.
• Debugging: Use po timestamp in Xcode’s console to inspect raw values.

This covers the essentials for working with timestamps in iOS. Apply these techniques for logging, API requests, and data storage.