DateTimeParser - Parse DateTime, NaiveDateTime, Time, or Date from strings

I’m excited to announce that TaxJar has developed and open-sourced DateTimeParser. We developed it because we found a need to parse user input into DateTimes or NaiveDateTimes. I didn’t find any existing libraries that did this not without knowing the format of the string in advance. Maybe it could help you out too?

Check out the repo:

Check it out at Hex:

Learn more about TaxJar: Special thanks to them for investing in my time to develop this and allowing me to open-source it! Also thanks to nimble_parsec for making this much easier to develop.


iex> DateTimeParser.parse_datetime("19 September 2018 08:15:22 AM")
{:ok, ~N[2018-09-19 08:15:22]}

iex> DateTimeParser.parse_datetime("2034-01-13")
{:ok, ~N[2034-01-13 00:00:00]}

iex> DateTimeParser.parse_date("2034-01-13")
{:ok, ~D[2034-01-13]}

iex> DateTimeParser.parse_date("01/01/2017")
{:ok, ~D[2017-01-01]}

iex> DateTimeParser.parse_datetime("1/1/18 3:24 PM")
{:ok, ~N[2018-01-01T15:24:00]}

iex> DateTimeParser.parse_datetime("1/1/18 3:24 PM", assume_utc: true)
{:ok, ~U[2018-01-01T15:24:00Z]}
# the ~U is a DateTime sigil introduced in Elixir 1.9.0

iex> DateTimeParser.parse_datetime(~s|"Dec 1, 2018 7:39:53 AM PST"|)
{:ok, ~U[2018-12-01T14:39:53Z]}
# Notice that the date is converted to UTC by default

iex> {:ok, datetime} = DateTimeParser.parse_datetime(~s|"Dec 1, 2018 7:39:53 AM PST"|, to_utc: false)
iex> datetime
#DateTime<2018-12-01 07:39:53-07:00 PDT PST8PDT>

iex> DateTimeParser.parse_time("10:13pm")
{:ok, ~T[22:13:00]}

iex> DateTimeParser.parse_time("10:13:34")
{:ok, ~T[10:13:34]}

1.0 is releasing soon! Yesterday, I published 1.0.rc-1 as a means to dogfood the recent changes. It’ll stay there for a bit to ensure no bugs pop up.

Changes since initial release:

  • Unix epoch times are now parsed
  • Serial (spreadsheet) times are now parsed
  • Added DateTimeParser.parse/2 to give the best answer it can give. Previously, you’d have to use parse_datetime, parse_date, or parse_time. Now you can throw strings into parse and get the most specific struct for what it could parse. For example, 2019-01-01 will give you a %Date{}; something @ 9:30pm will give you a %Time{}, etc.
  • [Breaking] some defaults changed. Previously, the lib would assume too much for you by default. For example if you used DateTimeParser.parse_datetime("2019-01-01") it would give you 2019-01-01T00:00:00. Where did the time come from? It was assumed. Now in 1.x this will not be the default. Also, it would auto-convert timezone’d timestamps to UTC; now you have to opt-in to that behavior.

if you’re interested, give it a shot and let me know what you think.