Backpack

Conveniences and tools that I've used throughout my Elixir projects

Installation

If available in Hex, the package can be installed by adding backpack to your list of dependencies in mix.exs:

def deps do
  [
    {:backpack, "~> 0.4.0"}
  ]
end

Includes

Moment

An ActiveSupport inspired way of handling dates and times.

Disclaimer

I'm well aware that timex has some of these functions. However, I'm not a fan of timex and usually use calendar instead. I find it to be more performant when dealing with collections.

This module works best with calendar, infact it uses calendar underneath for some of it's functions like Moment.strftime/2 to have a uniformed API.

However you may also keep things simple and stick to just storing date/time in UTC using NaiveDateTime/DateTime/Date.

iex(1)> alias Backpack.Moment
Backpack.Moment

# It can work with integers and output to unix timestamp
iex(2)> 1 |> Moment.day() |> Moment.ago()
1504123763921954000
iex(3)> 1 |> Moment.day() |> Moment.ago() |> Moment.from_unix!()
#DateTime<2017-08-30 20:09:43.939502Z>

# There are helper functions for working with DateTime/NaiveDateTime/Date
iex(4)> DateTime.utc_now() |> Moment.days_from_now(3)
#DateTime<2017-09-03 16:21:18.028638Z>
iex(5)> NaiveDateTime.utc_now() |> Moment.weeks_from_now(3)
~N[2017-09-21 16:25:31.817088]
iex(6)> NaiveDateTime.utc_now() |> Moment.weeks_from_now(3) |> Moment.quarter()
3
iex(7)> DateTime.utc_now() |> Moment.weeks_from_now(3) |> Moment.beginning_of_quarter()
#DateTime<2017-07-01 00:00:00.000000Z>
iex(8)> DateTime.utc_now() |> Moment.add(years: 1, days: -1)
#DateTime<2018-08-30 16:28:55.900591Z>
iex(9)> DateTime.utc_now() |> Moment.yesterday() |> Moment.next_year()
#DateTime<2018-08-30 16:29:08.464739Z>
iex(10)> Date.utc_today() |> Moment.end_of_month()
~D[2017-08-31]

# Some operations may convert a Date to NaiveDateTime when necessary with Time starting from 00:00:00.00000
iex(11)> Date.utc_today() |> Moment.end_of_day()
~N[2017-08-31 23:59:59.999999]
iex(12)> Date.utc_today() |> Moment.add(days: 1, weeks: 1, months: 1, years: 1, minutes: 20)
~N[2018-10-08 00:20:00.000000]

# However, it wont convert to NaiveDateTime unless there are time units
iex(13)> Date.utc_today() |> Moment.add(days: 1, weeks: 1, months: 1, years: 1)
~D[2018-10-08]

# The implementations of the protocol for different data types can interoperate
iex(15)> DateTime.utc_now() |> Moment.ago(1 |> Moment.day())
#DateTime<2017-08-30 16:41:50.362824Z>

Inflex

An ActiveSupport inspired way of handling strings built using binary pattern matching.

Regex is always avoided unless needed.