bitwalker/timex

Timex is a rich, comprehensive Date/Time library for Elixir projects, with full timezone support via the :tzdata package. If you need to manipulate dates, times, datetimes, timestamps, etc., then Timex is for you! It is very easy to use Timex types in place of default Erlang types, as well as Ecto types via the timex_ecto package.

The complete documentation for Timex is located here.

If you are coming from an earlier version of Timex, it is recommended that you evaluate whether or not the functionality provided by the standard library Calendar API is sufficient for your needs, as you may be able to avoid the dependency entirely.

For those that require Timex for one reason or another, Timex now delegates to the standard library where possible, and provides backward compatibility to Elixir 1.8 for APIs which are used. This is to avoid duplicating effort, and to ease the maintenance of this library in the future. Take a look at the documentation to see what APIs are available and how to use them. Many of them may have changed, been removed/renamed, or have had their semantics improved since early versions of the library, so if you are coming from an earlier version, you will need to review how you are using various APIs. The CHANGELOG is a helpful document to sort through what has changed in general.

Timex is primarily oriented around the Olson timezone database, and so you are encouraged to use those timezones in favor of alternatives. Timex does provide compatibility with the POSIX-TZ standard, which allows specification of custom timezones, see this document for more information. Timex does not provide support for timezones which do not adhere to one of those two standards. While Timex attempted to support timezone abbreviations without context in prior versions, this was broken, and has been removed.

There are some brief examples on usage below, but I highly recommend you review the API docs here, there are many examples, and some extra pages with richer documentation on specific subjects such as custom formatters/parsers, etc.

To use Timex, I recommend you add use Timex to the top of the module where you will be working with Timex modules, all it does is alias common types so you can work with them more comfortably. If you want to see the specific aliases added, check the top of the Timex module, in the __using__/1 macro definition.

Here's a few simple examples:

> use Timex
> Timex.today()
~D[2016-02-29]

> datetime = Timex.now()
#<DateTime(2016-02-29T12:30:30.120+00:00Z Etc/UTC)

> Timex.now("America/Chicago")
#<DateTime(2016-02-29T06:30:30.120-06:00 America/Chicago)

> Duration.now()
#<Duration(P46Y6M24DT21H57M33.977711S)>

> {:ok, default_str} = Timex.format(datetime, "{ISO:Extended}")
{:ok, "2016-02-29T12:30:30.120+00:00"}

> {:ok, relative_str} = Timex.shift(datetime, minutes: -3) |> Timex.format("{relative}", :relative)
{:ok, "3 minutes ago"}

> strftime_str = Timex.format!(datetime, "%FT%T%:z", :strftime)
"2016-02-29T12:30:30+00:00"

> Timex.parse(strftime_str, "{ISO:Extended}")
{:ok, #<DateTime(2016-02-29T12:30:30.120+00:00 Etc/Utc)}

> Timex.parse!(strftime_str, "%FT%T%:z", :strftime)
#<DateTime(2016-02-29T12:30:30.120+00:00 Etc/Utc)

> Duration.diff(Duration.now(), Duration.zero(), :days)
16850

> Timex.shift(date, days: 3)
~D[2016-03-03]

> Timex.shift(datetime, hours: 2, minutes: 13)
#<DateTime(2016-02-29T14:43:30.120Z Etc/UTC)>

> timezone = Timezone.get("America/Chicago", Timex.now())
#<TimezoneInfo(America/Chicago - CDT (-06:00:00))>

> Timezone.convert(datetime, timezone)
#<DateTime(2016-02-29T06:30:30.120-06:00 America/Chicago)>

> Timex.before?(Timex.today(), Timex.shift(Timex.today, days: 1))
true

> Timex.before?(Timex.shift(Timex.today(), days: 1), Timex.today())
false

> interval = Timex.Interval.new(from: ~D[2016-03-03], until: [days: 3])
%Timex.Interval{from: ~N[2016-03-03 00:00:00], left_open: false,
 right_open: true, step: [days: 1], until: ~N[2016-03-06 00:00:00]}

> ~D[2016-03-04] in interval
true

> ~N[2016-03-04 00:00:00] in interval
true

> ~N[2016-03-02 00:00:00] in interval
false

> Timex.Interval.overlaps?(Timex.Interval.new(from: ~D[2016-03-04], until: [days: 1]), interval)
true

> Timex.Interval.overlaps?(Timex.Interval.new(from: ~D[2016-03-07], until: [days: 1]), interval)
false

There are a ton of other functions, all of which work with Erlang datetime tuples, Date, NaiveDateTime, and DateTime. The Duration module contains functions for working with Durations, including Erlang timestamps (such as those returned from :timer.tc)

Timex exposes a number of extension points for you, in order to accommodate different use cases:

Timex itself defines its core operations on the Date, DateTime, and NaiveDateTime types using the Timex.Protocol protocol. From there, all other Timex functionality is derived. If you have custom date/datetime types you want to use with Timex, this is the protocol you would need to implement.

Timex also defines a Timex.Comparable protocol, which you can extend to add comparisons to custom date/datetime types.

You can provide your own formatter/parser for datetime strings by implementing the Timex.Format.DateTime.Formatter and/or Timex.Parse.DateTime.Parser behaviours, depending on your needs.

If you need to use Timex from within an escript, add {:tzdata, "~> 0.1.8", override: true} to your deps, more recent versions of :tzdata are unable to work in an escript because of the need to load ETS table files from priv, and due to the way ETS loads these files, it's not possible to do so.

If your build still throws an error after this, try removing the _build and deps folder. Then execute mix deps.unlock tzdata and mix deps.get.

Timex includes the Tzdata library for time zone data. Tzdata has an automatic update capability that fetches updates from IANA and which is enabled by default; if you want to disable it, check the Tzdata documentation for details.

This software is licensed under the MIT license.