fix: ts declaretion export the default class and types

[snowyu]

see #184

[codecov]

Codecov Report

Merging #188 into master will not change coverage.
The diff coverage is n/a.

@@          Coverage Diff          @@
##           master   #188   +/-   ##
=====================================
  Coverage     100%   100%           
=====================================
  Files           2      2           
  Lines         109    109           
  Branches       27     27           
=====================================
  Hits          109    109

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