Codecov Report

Merging #223 into master will increase coverage by 0.08%.
The diff coverage is 100%.

@@            Coverage Diff             @@
##           master     #223      +/-   ##
==========================================
+ Coverage   96.57%   96.65%   +0.08%     
==========================================
  Files          51       51              
  Lines        2455     2455              
  Branches      370      370              
==========================================
+ Hits         2371     2373       +2     
+ Misses         42       41       -1     
+ Partials       42       41       -1

I was wondering after looking at #222 - why do we have so many optional properties on the AST?
Wouldn't it be better for us to use empty arrays instead of just not setting a prop at all?

I can understand an optional field in the case of interface -> implements where it's not "supposed" to be there.
But like in the case of type parameters/arguments/annotations; wouldn't it be better for us to just set an empty array to save the plugin (and consumers) from doing undefined checks?

those nodes does no contain undefined arrays
TSTypeParameterDeclaration and TSTypeParameterInstantiation used for typeArguments and typeParameters contain in range <> tokens and they have array of params

TSTypeAnnotation contains in range : or =>

this is useful for setting up comments in AST, and without that there is no easy way to determine if comment is /* test */< /* test */ string /* test */> /* test */ before/after or within <>