Converting a date into a string

Elm:
Converting a date into a string

How to:

In Elm, you use the Date module to work with dates, and the elm/time package provides functions to convert dates to strings. Let’s dive in with some Elm code:

import Time exposing (Posix)
import Date

-- Assume we have a Posix timestamp
posixTime : Posix
posixTime = Time.millisToPosix 1672569600000

-- Convert the Posix to a Date
date : Date.Date
date = Date.fromPosix posixTime

-- Format date as a string
dateToString : String
dateToString = Date.toIsoString date

-- Output
dateToString --> "2023-01-01T00:00:00.000Z"

The line Date.toIsoString date is the one doing the heavy lifting by turning your Date.Date value into an ISO 8601 formatted string.

Deep Dive

Historically, Elm’s approach to dates and times has evolved with the language, aiming for more precision and consistency. By utilizing the elm/time package, Elm simplifies the process of time manipulation.

Alternatives for converting dates include using custom formatters if you want a specific way to show your dates. The Date module itself does not offer extensive formatting options, meaning if you need something beyond ISO 8601, you would turn to community packages such as justinmimbs/date for more formatting flexibility.

Implementation-wise, when you’re converting a date to a string in Elm, you’re handling time zones under the hood. Elm represents dates in UTC by default, which means no unexpected shifts in time when converting, unless you explicitly manage time zones with additional logic. This design choice is meant to reduce bugs and inconsistencies, especially when dealing with servers and clients in different time zones.

Elm:Converting a date into a string

How to:

Deep Dive

See Also

Elm:
Converting a date into a string