See https://github.com/retorquere/zotero-better-bibtex/issues/811#issuecomment-346939090

Exported_Items.bib

@unpublished{t1,
  title = {A Manuscript: 2014-12-31/2015-01-01},
  author = {Doe, John},
  date = {2014-12-31/2015-01-01},
  origdate = {1777-07-27/1888-08-28},
  eventdate = {1888-08-28},
  urldate = {2014-12-31~}
}

@book{t2,
  title = {Container, Event-Date, and Submitted Test},
  author = {Doe, John},
  eventdate = {1800-01-01/1800-12-31},
  urldate = {13th cent}
}

@book{t3,
  title = {Open-Ended Date Range Test: 2014-12-31/},
  author = {Doe, John},
  date = {2014-12-31/}
}

@book{t4,
  title = {Single Date Test: 2014-12-31},
  author = {Doe, John},
  date = {2014-12-31}
}

@book{t5,
  title = {{{BC}} Tests: -0333},
  author = {Doe, John},
  date = {-0333},
  origdate = {-0333/-0332},
  eventdate = {0000},
  urldate = {-0332-11-05}
}

@book{t6,
  title = {{{BC}} Tests 2: -0099-07-12/-0043-03-15},
  author = {Doe, John},
  date = {-0099-07-12/-0043-03-15}
}

@article{StaigerPoliticsFilmCanons1985,
  eprinttype = {jstor},
  eprint = {1225428},
  title = {The {{Politics}} of {{Film Canons}}: Printemps 1985},
  volume = {24},
  number = {3},
  journaltitle = {Cinema Journal},
  author = {Staiger, Janet},
  date = {1985-21},
  pages = {4--23}
}

@online{AuthorTitle2017232017,
  title = {Title: 2017-23},
  author = {{Author}},
  date = {2017-23}
}

@online{AuthorEDTFdaterange2011c,
  title = {{{EDTF}} Date Range, circa Begin: 2011-05-25\textasciitilde/2012-06-26},
  author = {{Author}},
  date = {2011-05-25~/2012-06-26}
}

@online{AuthorEDTFdaterange2011d,
  title = {{{EDTF}} Date Range, circa Begin \& End: 2011-05-25{\textasciitilde}/2012-06-26\textasciitilde{}},
  author = {{Author}},
  date = {2011-05-25~/2012-06-26~}
}

@online{AuthorEDTFdaterange2011e,
  title = {{{EDTF}} Date Range, circa End: 2011-05-25/2012-06-26\textasciitilde{}},
  author = {{Author}},
  date = {2011-05-25/2012-06-26~}
}

@online{AuthorEDTFdateYYYYMM2011a,
  title = {{{EDTF}} Date {{YYYY}}-{{MM}}\textasciitilde{} [Month Precision \& circa]: 2011-05\textasciitilde{}},
  author = {{Author}},
  date = {2011-05~}
}

@online{AuthorSeasoncirca2017242017,
  title = {Season circa: : 2017-24\textasciitilde{}},
  author = {{Author}},
  date = {2017-24~}
}