Example for my iDDD with Go blog article series at https://medium.com/@TonyBologni

currentState.go

package customer

import (
    "github.com/AntonStoeckl/go-iddd/service/customeraccounts/application/domain"
    "github.com/AntonStoeckl/go-iddd/service/customeraccounts/application/domain/customer/value"
    "github.com/AntonStoeckl/go-iddd/service/shared/es"
)

type currentState struct {
    id                           value.CustomerID
    personName                   value.PersonName
    emailAddress                 value.EmailAddress
    emailAddressConfirmationHash value.ConfirmationHash
    isEmailAddressConfirmed      bool
    isDeleted                    bool
    currentStreamVersion         uint
}

func buildCurrentStateFrom(eventStream es.EventStream) currentState {
    customer := currentState{}

    for _, event := range eventStream {
        switch actualEvent := event.(type) {
        case domain.CustomerRegistered:
            customer.id = actualEvent.CustomerID()
            customer.personName = actualEvent.PersonName()
            customer.emailAddress = actualEvent.EmailAddress()
            customer.emailAddressConfirmationHash = actualEvent.ConfirmationHash()
        case domain.CustomerEmailAddressConfirmed:
            customer.isEmailAddressConfirmed = true
        case domain.CustomerEmailAddressChanged:
            customer.emailAddress = actualEvent.EmailAddress()
            customer.emailAddressConfirmationHash = actualEvent.ConfirmationHash()
            customer.isEmailAddressConfirmed = false
        case domain.CustomerNameChanged:
            customer.personName = actualEvent.PersonName()
        case domain.CustomerDeleted:
            customer.isDeleted = true
        }

        customer.currentStreamVersion = event.Meta().StreamVersion()
    }

    return customer
}