refactor: create enum for --builtin doc flag (#17423)

cli/args/flags.rs

@@ -94,11 +94,23 @@ pub struct CoverageFlags {
   pub lcov: bool,
 }
 
+#[derive(Clone, Debug, Eq, PartialEq)]
+pub enum DocSourceFileFlag {
+  Builtin,
+  Path(String),
+}
+
+impl Default for DocSourceFileFlag {
+  fn default() -> Self {
+    Self::Builtin
+  }
+}
+
 #[derive(Clone, Debug, Eq, PartialEq)]
 pub struct DocFlags {
   pub private: bool,
   pub json: bool,
-  pub source_file: Option<String>,
+  pub source_file: DocSourceFileFlag,
   pub filter: Option<String>,
 }
 
@@ -2444,7 +2456,16 @@ fn doc_parse(flags: &mut Flags, matches: &clap::ArgMatches) {
   import_map_arg_parse(flags, matches);
   reload_arg_parse(flags, matches);
 
-  let source_file = matches.value_of("source_file").map(String::from);
+  let source_file = matches
+    .value_of("source_file")
+    .map(|value| {
+      if value == "--builtin" {
+        DocSourceFileFlag::Builtin
+      } else {
+        DocSourceFileFlag::Path(value.to_string())
+      }
+    })
+    .unwrap_or_default();
   let private = matches.is_present("private");
   let json = matches.is_present("json");
   let filter = matches.value_of("filter").map(String::from);
@@ -4916,7 +4937,7 @@ mod tests {
       r.unwrap(),
       Flags {
         subcommand: DenoSubcommand::Doc(DocFlags {
-          source_file: Some("script.ts".to_owned()),
+          source_file: DocSourceFileFlag::Path("script.ts".to_owned()),
           private: false,
           json: false,
           filter: None,
@@ -5922,7 +5943,7 @@ mod tests {
         subcommand: DenoSubcommand::Doc(DocFlags {
           private: false,
           json: true,
-          source_file: Some("path/to/module.ts".to_string()),
+          source_file: DocSourceFileFlag::Path("path/to/module.ts".to_string()),
           filter: None,
         }),
         ..Flags::default()
@@ -5941,7 +5962,7 @@ mod tests {
         subcommand: DenoSubcommand::Doc(DocFlags {
           private: false,
           json: false,
-          source_file: Some("path/to/module.ts".to_string()),
+          source_file: DocSourceFileFlag::Path("path/to/module.ts".to_string()),
           filter: Some("SomeClass.someField".to_string()),
         }),
         ..Flags::default()
@@ -5955,7 +5976,7 @@ mod tests {
         subcommand: DenoSubcommand::Doc(DocFlags {
           private: false,
           json: false,
-          source_file: None,
+          source_file: Default::default(),
           filter: None,
         }),
         ..Flags::default()
@@ -5969,7 +5990,7 @@ mod tests {
         subcommand: DenoSubcommand::Doc(DocFlags {
           private: false,
           json: false,
-          source_file: Some("--builtin".to_string()),
+          source_file: DocSourceFileFlag::Builtin,
           filter: Some("Deno.Listener".to_string()),
         }),
         ..Flags::default()
@@ -5984,7 +6005,7 @@ mod tests {
         subcommand: DenoSubcommand::Doc(DocFlags {
           private: true,
           json: false,
-          source_file: Some("path/to/module.js".to_string()),
+          source_file: DocSourceFileFlag::Path("path/to/module.js".to_string()),
           filter: None,
         }),
         ..Flags::default()

cli/tools/doc.rs

@@ -1,6 +1,7 @@
 // Copyright 2018-2023 the Deno authors. All rights reserved. MIT license.
 
 use crate::args::DocFlags;
+use crate::args::DocSourceFileFlag;
 use crate::args::Flags;
 use crate::colors;
 use crate::display::write_json_to_stdout;
@@ -22,11 +23,9 @@ pub async fn print_docs(
   doc_flags: DocFlags,
 ) -> Result<(), AnyError> {
   let ps = ProcState::build(flags).await?;
-  let source_file = doc_flags
-    .source_file
-    .unwrap_or_else(|| "--builtin".to_string());
 
-  let mut doc_nodes = if source_file == "--builtin" {
+  let mut doc_nodes = match doc_flags.source_file {
+    DocSourceFileFlag::Builtin => {
       let source_file_specifier =
         ModuleSpecifier::parse("deno://lib.deno.d.ts").unwrap();
       let content = get_types_declaration_file_text(ps.options.unstable());
@@ -60,7 +59,8 @@ pub async fn print_docs(
         analyzer.as_capturing_parser(),
       );
       doc_parser.parse_module(&source_file_specifier)?.definitions
-  } else {
+    }
+    DocSourceFileFlag::Path(source_file) => {
       let module_specifier = resolve_url_or_path(&source_file)?;
 
       // If the root module has external types, the module graph won't redirect it,
@@ -87,6 +87,7 @@ pub async fn print_docs(
         ps.parsed_source_cache.as_capturing_parser(),
       );
       doc_parser.parse_with_reexports(&root_specifier)?
+    }
   };
 
   if doc_flags.json {