checkTypes: "natives" should be "primitives" (see notes below)

[gajus]

typeof true
"boolean"

OK

typeof 1
"number"

OK

typeof 'foo'
"string"

OK

typeof {}
"object"

NOT OK

[].constructor.name
"Array"

OK

new Date().constructor.name
"Date"

OK

/test/.constructor.name
"RegExp"

OK

[qfox]

Well, but:

({}).constructor.name
"Object"

("").constructor.name
"String"

[gajus]

For some reason I assumed that plain object does not have .constructor.name.

[qfox]

@gajus Just noticed that natives should be primitives: https://developer.mozilla.org/en-US/docs/Glossary/Primitive
Oopsie!