Получить местное время человека по часовому поясу в вязе

Вы захотите преобразовать эти строки zone в настоящие Time.Zone, что можно сделать с помощью Библиотека часовых поясов justinmimbs.

Затем вам нужно будет получить текущее время с помощью чего-то вроде Time.every и преобразовать его в местные части с помощью Time.Extra.posixToParts.

Некоторый пример кода:

module Main exposing (main)

import Browser
import Dict
import Html exposing (Html, li, text, ul)
import Time exposing (Month(..))
import Time.Extra
import TimeZone


type Msg
    = Tick Time.Posix


type alias Model =
    { now : Time.Posix }


type alias RawSupporter =
    { supportName : String
    , numberOfClient : Int
    , zone : String
    , startTime : String
    , endTime : String
    }


type alias Supporter =
    { supportName : String
    , numberOfClient : Int
    , zone : Maybe Time.Zone
    , rawZone : String
    , startTime : String
    , endTime : String
    }


rawSupporters : List RawSupporter
rawSupporters =
    [ { supportName = "Maynard Kaminski"
      , numberOfClient = 12
      , zone = "Europe/Moscow"
      , startTime = "9 am"
      , endTime = "1 pm"
      }
    , { supportName = "Belle Willett"
      , numberOfClient = 8
      , zone = "Canada/Eastern"
      , startTime = "2 pm"
      , endTime = "6 pm"
      }
    , { supportName = "Gaylene Hickson"
      , numberOfClient = 7
      , zone = "Africa/Nairobi"
      , startTime = "6 pm"
      , endTime = "10 pm"
      }
    , { supportName = "Cinthia Talbert"
      , numberOfClient = 4
      , zone = "Asia/Tokyo"
      , startTime = "2 pm"
      , endTime = "6 pm"
      }
    , { supportName = "Sydney Crenshaw"
      , numberOfClient = 7
      , zone = "Pacific/Honolulu"
      , startTime = "6 am"
      , endTime = "10 am"
      }
    ]


supporters : List Supporter
supporters =
    rawSupporters
        |> List.map
            (\raw ->
                { supportName = raw.supportName
                , numberOfClient = raw.numberOfClient
                , zone =
                    TimeZone.zones
                        |> Dict.get raw.zone
                        |> Maybe.map (\evaluate -> evaluate ())
                , rawZone = raw.zone
                , startTime = raw.startTime
                , endTime = raw.endTime
                }
            )


viewSupporter : Time.Posix -> Supporter -> Html msg
viewSupporter now supporter =
    let
        parts =
            supporter.zone
                |> Maybe.map
                    (\zone ->
                        Time.Extra.posixToParts zone now
                    )

        localTimeDisplay =
            case parts of
                Just { year, month, day, hour, minute, second, millisecond } ->
                    ([ [ year, monthNum month, day ]
                        |> List.map String.fromInt
                        |> String.join "-"
                     , [ hour, minute, second ]
                        |> List.map String.fromInt
                        |> String.join ":"
                     ]
                        |> String.join " "
                    )
                        ++ " (local time)"

                Nothing ->
                    "<Not a valid timezone: '" ++ supporter.rawZone ++ "'>"
    in
    [ supporter.supportName
    , " ("
    , String.fromInt supporter.numberOfClient
    , ") "
    , supporter.startTime
    , " - "
    , supporter.endTime
    , " "
    , localTimeDisplay
    ]
        |> List.map text
        |> li []


monthNum : Month -> Int
monthNum m =
    case m of
        Jan ->
            1

        Feb ->
            2

        Mar ->
            3

        Apr ->
            4

        May ->
            5

        Jun ->
            6

        Jul ->
            7

        Aug ->
            8

        Sep ->
            9

        Oct ->
            10

        Nov ->
            11

        Dec ->
            12


update : Msg -> Model -> ( Model, Cmd Msg )
update msg model =
    case msg of
        Tick newTime ->
            ( { model | now = newTime }, Cmd.none )


view : Model -> Html Msg
view model =
    supporters
        |> List.map (viewSupporter model.now)
        |> ul []


main : Program () Model Msg
main =
    Browser.element
        { init = \() -> ( { now = Time.millisToPosix 0 }, Cmd.none )
        , view = view
        , update = update
        , subscriptions = \_ -> Time.every 1000 Tick
        }

Вот тот же код работает на ellie-app.com.