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Timestamps - Kotlin SDK

You cannot store Kotlin's built-in Date or Instant types in Realm Database. Instead, use the RealmInstant type, which stores time information as a UNIX epoch timestamp.

If you need timestamp data in a form other than RealmInstant, you can add conversion code to your model class based on the following example:

// model class that stores an Instant (kotlinx-datetime) field as a RealmInstant via a conversion
class RealmInstantConversion : RealmObject {
    private var _timestamp: RealmInstant = RealmInstant.from(0, 0)
    public var timestamp: Instant
        get() {
            return _timestamp.toInstant()
        }
        set(value) {
            _timestamp = value.toRealmInstant()
        }
}
fun RealmInstant.toInstant(): Instant {
    val sec: Long = this.epochSeconds
    // The value always lies in the range `-999_999_999..999_999_999`.
    // minus for timestamps before epoch, positive for after
    val nano: Int = this.nanosecondsOfSecond
    return if (sec >= 0) { // For positive timestamps, conversion can happen directly
        Instant.fromEpochSeconds(sec, nano.toLong())
    } else {
        // For negative timestamps, RealmInstant starts from the higher value with negative
        // nanoseconds, while Instant starts from the lower value with positive nanoseconds
        // TODO This probably breaks at edge cases like MIN/MAX
        Instant.fromEpochSeconds(sec - 1, 1_000_000 + nano.toLong())
    }
}
fun Instant.toRealmInstant(): RealmInstant {
    val sec: Long = this.epochSeconds
    // The value is always positive and lies in the range `0..999_999_999`.
    val nano: Int = this.nanosecondsOfSecond
    return if (sec >= 0) { // For positive timestamps, conversion can happen directly
        RealmInstant.from(sec, nano)
    } else {
        // For negative timestamps, RealmInstant starts from the higher value with negative
        // nanoseconds, while Instant starts from the lower value with positive nanoseconds
        // TODO This probably breaks at edge cases like MIN/MAX
        RealmInstant.from(sec + 1, -1_000_000 + nano)
    }
}

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