A date-time string at UTC, such as 2007-12-03T10:15:30Z, compliant with the
date-time format outlined in section 5.6 of the RFC 3339 profile of the ISO 8601 standard for representation of dates and times using the Gregorian calendar.
This scalar is a description of an exact instant on the time-line such as the instant that a user account was created.
This scalar ignores leap seconds (thereby assuming that a minute constitutes of 59 seconds). In this respect it diverges from the RFC 3339 profile.
Where an RFC 3339 compliant date-time string has a time-zone other than UTC, it is shifted to UTC. For example, the date-time string "2016-01-01T14:10:20+01:00" is shifted to "2016-01-01T13:10:20Z".
When expected as an input type, only RFC 3339 compliant date-time strings are accepted. All other input values raise a query error indicating an incorrect type.
Taken from graphql-iso-date