Detect the OpenAPI/Swagger version from a document.
Returns undefined when the document declares neither swagger nor
openapi strings, or when the declared version string is malformed
(missing parts or non-numeric segments). Number("abc") yields NaN,
which parts[i] ?? default does NOT replace — nullish coalescing only
substitutes null/undefined — so any unparseable segment surfaces
as undefined rather than a silent fabricated default.
Detect the OpenAPI/Swagger version from a document.
Returns
undefinedwhen the document declares neitherswaggernoropenapistrings, or when the declared version string is malformed (missing parts or non-numeric segments).Number("abc")yieldsNaN, whichparts[i] ?? defaultdoes NOT replace — nullish coalescing only substitutesnull/undefined— so any unparseable segment surfaces asundefinedrather than a silent fabricated default.