Not able to use lazy var in struct in array's firstIndex Method

Question

I have seen couple of questions but Didn't find solution and a reason

Here is struct

struct MovementFormattedData {
   ... Other properties ...
   lazy var timeAsDate:Date?  = {
       return MovementFormattedData.getUTCDate(movementTime: movementTime)
    }()



  static func getUTCDate(movementTime:String?) -> Date? {
        // return date
     }
}

Now I have array

var movements :[MovementFormattedData] = []

When I try

  self?.movements.firstIndex(where: {$0.timeAsDate > Date() })

I am getting

Cannot use mutating getter on immutable value: '$0' is immutable

I am not modifying $0 anywhere. I am just access the property

Please help

Answer 1

I think initialising timeAsDate counts as mutating so a lazy variable might not be what you need.

You could try a computed variable instead so long as you don't need to manually change it.

var timeAsDate: Date? {
   return MovementFormattedData.getUTCDate(movementTime: movementTime)
}

Answer 2

No necessary to use lazy var

var timeAsDate: Date? {
    return MovementFormattedData.getUTCDate(movementTime: movementTime)
}

Answer 3

lazy property is mutating getter and you cant use it with $0 because $0 is immutable

see following code block

struct MovementFormattedData {
   ... Other properties ...
   var timeAsDate: Date? {
       return MovementFormattedData.getUTCDate(movementTime: movementTime)
    }

  static func getUTCDate(movementTime:String?) -> Date? {
        // return date
     }
}

var movements: [MovementFormattedData] = []

self?.movements.firstIndex(where: { $0.timeAsDate ?? Date() > Date() })