feat(doc): handle basic reexports (#4625)

5 files changed, 488 insertions, 129 deletions

diff --git a/cli/doc/module.rs b/cli/doc/module.rs
index e1d629ccf..ba62902dc 100644
--- a/cli/doc/module.rs
+++ b/cli/doc/module.rs
@@ -147,42 +147,3 @@ pub fn get_doc_node_for_export_decl(
     }
   }
 }
-
-#[allow(unused)]
-pub fn get_doc_nodes_for_named_export(
-  doc_parser: &DocParser,
-  named_export: &swc_ecma_ast::NamedExport,
-) -> Vec<DocNode> {
-  let file_name = named_export.src.as_ref().expect("").value.to_string();
-  // TODO: resolve specifier
-  let source_code =
-    std::fs::read_to_string(&file_name).expect("Failed to read file");
-  let doc_nodes = doc_parser
-    .parse(file_name, source_code)
-    .expect("Failed to print docs");
-  let reexports: Vec<String> = named_export
-    .specifiers
-    .iter()
-    .map(|export_specifier| {
-      use crate::swc_ecma_ast::ExportSpecifier::*;
-
-      match export_specifier {
-        Named(named_export_specifier) => {
-          Some(named_export_specifier.orig.sym.to_string())
-        }
-        // TODO:
-        Namespace(_) => None,
-        Default(_) => None,
-      }
-    })
-    .filter(|s| s.is_some())
-    .map(|s| s.unwrap())
-    .collect();
-
-  let reexports_docs: Vec<DocNode> = doc_nodes
-    .into_iter()
-    .filter(|doc_node| reexports.contains(&doc_node.name))
-    .collect();
-
-  reexports_docs
-}
diff --git a/cli/doc/node.rs b/cli/doc/node.rs
index e1e83ad0d..1be3ba7b1 100644
--- a/cli/doc/node.rs
+++ b/cli/doc/node.rs
@@ -48,6 +48,35 @@ impl Into<Location> for swc_common::Loc {
 
 #[derive(Debug, Serialize, Clone)]
 #[serde(rename_all = "camelCase")]
+pub enum ReexportKind {
+  /// export * from "./path/to/module.js";
+  All,
+  /// export * as someNamespace from "./path/to/module.js";
+  Namespace(String),
+  /// export default from "./path/to/module.js";
+  Default,
+  /// (identifier, optional alias)
+  /// export { foo } from "./path/to/module.js";
+  /// export { foo as bar } from "./path/to/module.js";
+  Named(String, Option<String>),
+}
+
+#[derive(Debug, Serialize, Clone)]
+#[serde(rename_all = "camelCase")]
+pub struct Reexport {
+  pub kind: ReexportKind,
+  pub src: String,
+}
+
+#[derive(Debug, Serialize, Clone)]
+#[serde(rename_all = "camelCase")]
+pub struct ModuleDoc {
+  pub exports: Vec<DocNode>,
+  pub reexports: Vec<Reexport>,
+}
+
+#[derive(Debug, Serialize, Clone)]
+#[serde(rename_all = "camelCase")]
 pub struct DocNode {
   pub kind: DocNodeKind,
   pub name: String,
diff --git a/cli/doc/parser.rs b/cli/doc/parser.rs
index 7a8fee56f..7c67f8d09 100644
--- a/cli/doc/parser.rs
+++ b/cli/doc/parser.rs
@@ -1,4 +1,5 @@
 // Copyright 2018-2020 the Deno authors. All rights reserved. MIT license.
+use crate::op_error::OpError;
 use crate::swc_common;
 use crate::swc_common::comments::CommentKind;
 use crate::swc_common::comments::Comments;
@@ -22,34 +23,87 @@ use crate::swc_ecma_parser::Session;
 use crate::swc_ecma_parser::SourceFileInput;
 use crate::swc_ecma_parser::Syntax;
 use crate::swc_ecma_parser::TsConfig;
+
+use deno_core::ErrBox;
+use deno_core::ModuleSpecifier;
+use futures::Future;
 use regex::Regex;
+use std::collections::HashMap;
+use std::error::Error;
+use std::fmt;
+use std::pin::Pin;
 use std::sync::Arc;
 use std::sync::RwLock;
 
+use super::namespace::NamespaceDef;
+use super::node;
+use super::node::ModuleDoc;
 use super::DocNode;
 use super::DocNodeKind;
 use super::Location;
 
-pub type SwcDiagnostics = Vec<Diagnostic>;
+#[derive(Clone, Debug)]
+pub struct SwcDiagnosticBuffer {
+  pub diagnostics: Vec<Diagnostic>,
+}
+
+impl Error for SwcDiagnosticBuffer {}
+
+impl fmt::Display for SwcDiagnosticBuffer {
+  fn fmt(&self, f: &mut fmt::Formatter<'_>) -> fmt::Result {
+    let msg = self
+      .diagnostics
+      .iter()
+      .map(|d| d.message())
+      .collect::<Vec<String>>()
+      .join(",");
+
+    f.pad(&msg)
+  }
+}
+
+#[derive(Clone)]
+pub struct SwcErrorBuffer(Arc<RwLock<SwcDiagnosticBuffer>>);
 
-#[derive(Clone, Default)]
-pub struct BufferedError(Arc<RwLock<SwcDiagnostics>>);
+impl SwcErrorBuffer {
+  pub fn default() -> Self {
+    Self(Arc::new(RwLock::new(SwcDiagnosticBuffer {
+      diagnostics: vec![],
+    })))
+  }
+}
 
-impl Emitter for BufferedError {
+impl Emitter for SwcErrorBuffer {
   fn emit(&mut self, db: &DiagnosticBuilder) {
-    self.0.write().unwrap().push((**db).clone());
+    self.0.write().unwrap().diagnostics.push((**db).clone());
   }
 }
 
-impl From<BufferedError> for Vec<Diagnostic> {
-  fn from(buf: BufferedError) -> Self {
+impl From<SwcErrorBuffer> for SwcDiagnosticBuffer {
+  fn from(buf: SwcErrorBuffer) -> Self {
     let s = buf.0.read().unwrap();
     s.clone()
   }
 }
 
+pub trait DocFileLoader {
+  fn resolve(
+    &self,
+    specifier: &str,
+    referrer: &str,
+  ) -> Result<ModuleSpecifier, OpError> {
+    ModuleSpecifier::resolve_import(specifier, referrer).map_err(OpError::from)
+  }
+
+  fn load_source_code(
+    &self,
+    specifier: &str,
+  ) -> Pin<Box<dyn Future<Output = Result<String, OpError>>>>;
+}
+
 pub struct DocParser {
-  pub buffered_error: BufferedError,
+  pub loader: Box<dyn DocFileLoader>,
+  pub buffered_error: SwcErrorBuffer,
   pub source_map: Arc<SourceMap>,
   pub handler: Handler,
   pub comments: Comments,
@@ -57,8 +111,8 @@ pub struct DocParser {
 }
 
 impl DocParser {
-  pub fn default() -> Self {
-    let buffered_error = BufferedError::default();
+  pub fn new(loader: Box<dyn DocFileLoader>) -> Self {
+    let buffered_error = SwcErrorBuffer::default();
 
     let handler = Handler::with_emitter_and_flags(
       Box::new(buffered_error.clone()),
@@ -70,6 +124,7 @@ impl DocParser {
     );
 
     DocParser {
+      loader,
       buffered_error,
       source_map: Arc::new(SourceMap::default()),
       handler,
@@ -78,15 +133,16 @@ impl DocParser {
     }
   }
 
-  pub fn parse(
+  fn parse_module(
     &self,
-    file_name: String,
-    source_code: String,
-  ) -> Result<Vec<DocNode>, SwcDiagnostics> {
+    file_name: &str,
+    source_code: &str,
+  ) -> Result<ModuleDoc, SwcDiagnosticBuffer> {
     swc_common::GLOBALS.set(&self.globals, || {
-      let swc_source_file = self
-        .source_map
-        .new_source_file(FileName::Custom(file_name), source_code);
+      let swc_source_file = self.source_map.new_source_file(
+        FileName::Custom(file_name.to_string()),
+        source_code.to_string(),
+      );
 
       let buffered_err = self.buffered_error.clone();
       let session = Session {
@@ -112,15 +168,130 @@ impl DocParser {
           .parse_module()
           .map_err(move |mut err: DiagnosticBuilder| {
             err.cancel();
-            SwcDiagnostics::from(buffered_err)
+            SwcDiagnosticBuffer::from(buffered_err)
           })?;
 
-      let doc_entries = self.get_doc_nodes_for_module_body(module.body);
-      Ok(doc_entries)
+      let doc_entries = self.get_doc_nodes_for_module_body(module.body.clone());
+      let reexports = self.get_reexports_for_module_body(module.body);
+      let module_doc = ModuleDoc {
+        exports: doc_entries,
+        reexports,
+      };
+      Ok(module_doc)
     })
   }
 
-  pub fn get_doc_nodes_for_module_decl(
+  pub async fn parse(&self, file_name: &str) -> Result<Vec<DocNode>, ErrBox> {
+    let source_code = self.loader.load_source_code(file_name).await?;
+
+    let module_doc = self.parse_module(file_name, &source_code)?;
+    Ok(module_doc.exports)
+  }
+
+  async fn flatten_reexports(
+    &self,
+    reexports: &[node::Reexport],
+    referrer: &str,
+  ) -> Result<Vec<DocNode>, ErrBox> {
+    let mut by_src: HashMap<String, Vec<node::Reexport>> = HashMap::new();
+
+    let mut processed_reexports: Vec<DocNode> = vec![];
+
+    for reexport in reexports {
+      if by_src.get(&reexport.src).is_none() {
+        by_src.insert(reexport.src.to_string(), vec![]);
+      }
+
+      let bucket = by_src.get_mut(&reexport.src).unwrap();
+      bucket.push(reexport.clone());
+    }
+
+    for specifier in by_src.keys() {
+      let resolved_specifier = self.loader.resolve(specifier, referrer)?;
+      let doc_nodes = self.parse(&resolved_specifier.to_string()).await?;
+      let reexports_for_specifier = by_src.get(specifier).unwrap();
+
+      for reexport in reexports_for_specifier {
+        match &reexport.kind {
+          node::ReexportKind::All => {
+            processed_reexports.extend(doc_nodes.clone())
+          }
+          node::ReexportKind::Namespace(ns_name) => {
+            let ns_def = NamespaceDef {
+              elements: doc_nodes.clone(),
+            };
+            let ns_doc_node = DocNode {
+              kind: DocNodeKind::Namespace,
+              name: ns_name.to_string(),
+              location: Location {
+                filename: specifier.to_string(),
+                line: 1,
+                col: 0,
+              },
+              js_doc: None,
+              namespace_def: Some(ns_def),
+              enum_def: None,
+              type_alias_def: None,
+              interface_def: None,
+              variable_def: None,
+              function_def: None,
+              class_def: None,
+            };
+            processed_reexports.push(ns_doc_node);
+          }
+          node::ReexportKind::Named(ident, maybe_alias) => {
+            // Try to find reexport.
+            // NOTE: the reexport might actually be reexport from another
+            // module; for now we're skipping nested reexports.
+            let maybe_doc_node =
+              doc_nodes.iter().find(|node| &node.name == ident);
+
+            if let Some(doc_node) = maybe_doc_node {
+              let doc_node = doc_node.clone();
+              let doc_node = if let Some(alias) = maybe_alias {
+                DocNode {
+                  name: alias.to_string(),
+                  ..doc_node
+                }
+              } else {
+                doc_node
+              };
+
+              processed_reexports.push(doc_node);
+            }
+          }
+          node::ReexportKind::Default => {
+            // TODO: handle default export from child module
+          }
+        }
+      }
+    }
+
+    Ok(processed_reexports)
+  }
+
+  pub async fn parse_with_reexports(
+    &self,
+    file_name: &str,
+  ) -> Result<Vec<DocNode>, ErrBox> {
+    let source_code = self.loader.load_source_code(file_name).await?;
+
+    let module_doc = self.parse_module(file_name, &source_code)?;
+
+    let flattened_docs = if !module_doc.reexports.is_empty() {
+      let mut flattenned_reexports = self
+        .flatten_reexports(&module_doc.reexports, file_name)
+        .await?;
+      flattenned_reexports.extend(module_doc.exports);
+      flattenned_reexports
+    } else {
+      module_doc.exports
+    };
+
+    Ok(flattened_docs)
+  }
+
+  pub fn get_doc_nodes_for_module_exports(
     &self,
     module_decl: &ModuleDecl,
   ) -> Vec<DocNode> {
@@ -131,16 +302,6 @@ impl DocParser {
           export_decl,
         )]
       }
-      ModuleDecl::ExportNamed(_named_export) => {
-        vec![]
-        // TODO(bartlomieju):
-        // super::module::get_doc_nodes_for_named_export(self, named_export)
-      }
-      ModuleDecl::ExportDefaultDecl(_) => vec![],
-      ModuleDecl::ExportDefaultExpr(_) => vec![],
-      ModuleDecl::ExportAll(_) => vec![],
-      ModuleDecl::TsExportAssignment(_) => vec![],
-      ModuleDecl::TsNamespaceExport(_) => vec![],
       _ => vec![],
     }
   }
@@ -316,6 +477,67 @@ impl DocParser {
     }
   }
 
+  pub fn get_reexports_for_module_body(
+    &self,
+    module_body: Vec<swc_ecma_ast::ModuleItem>,
+  ) -> Vec<node::Reexport> {
+    use swc_ecma_ast::ExportSpecifier::*;
+
+    let mut reexports: Vec<node::Reexport> = vec![];
+
+    for node in module_body.iter() {
+      if let swc_ecma_ast::ModuleItem::ModuleDecl(module_decl) = node {
+        let r = match module_decl {
+          ModuleDecl::ExportNamed(named_export) => {
+            if let Some(src) = &named_export.src {
+              let src_str = src.value.to_string();
+              named_export
+                .specifiers
+                .iter()
+                .map(|export_specifier| match export_specifier {
+                  Namespace(ns_export) => node::Reexport {
+                    kind: node::ReexportKind::Namespace(
+                      ns_export.name.sym.to_string(),
+                    ),
+                    src: src_str.to_string(),
+                  },
+                  Default(_) => node::Reexport {
+                    kind: node::ReexportKind::Default,
+                    src: src_str.to_string(),
+                  },
+                  Named(named_export) => {
+                    let ident = named_export.orig.sym.to_string();
+                    let maybe_alias =
+                      named_export.exported.as_ref().map(|e| e.sym.to_string());
+                    let kind = node::ReexportKind::Named(ident, maybe_alias);
+                    node::Reexport {
+                      kind,
+                      src: src_str.to_string(),
+                    }
+                  }
+                })
+                .collect::<Vec<node::Reexport>>()
+            } else {
+              vec![]
+            }
+          }
+          ModuleDecl::ExportAll(export_all) => {
+            let reexport = node::Reexport {
+              kind: node::ReexportKind::All,
+              src: export_all.src.value.to_string(),
+            };
+            vec![reexport]
+          }
+          _ => vec![],
+        };
+
+        reexports.extend(r);
+      }
+    }
+
+    reexports
+  }
+
   pub fn get_doc_nodes_for_module_body(
     &self,
     module_body: Vec<swc_ecma_ast::ModuleItem>,
@@ -324,7 +546,8 @@ impl DocParser {
     for node in module_body.iter() {
       match node {
         swc_ecma_ast::ModuleItem::ModuleDecl(module_decl) => {
-          doc_entries.extend(self.get_doc_nodes_for_module_decl(module_decl));
+          doc_entries
+            .extend(self.get_doc_nodes_for_module_exports(module_decl));
         }
         swc_ecma_ast::ModuleItem::Stmt(stmt) => {
           if let Some(doc_node) = self.get_doc_node_for_stmt(stmt) {
diff --git a/cli/doc/tests.rs b/cli/doc/tests.rs
index 9432ba095..337f32466 100644
--- a/cli/doc/tests.rs
+++ b/cli/doc/tests.rs
@@ -4,8 +4,47 @@ use crate::colors;
 use serde_json;
 use serde_json::json;
 
-#[test]
-fn export_fn() {
+use super::parser::DocFileLoader;
+use crate::op_error::OpError;
+use std::collections::HashMap;
+
+use futures::Future;
+use futures::FutureExt;
+use std::pin::Pin;
+
+pub struct TestLoader {
+  files: HashMap<String, String>,
+}
+
+impl TestLoader {
+  pub fn new(files_vec: Vec<(String, String)>) -> Box<Self> {
+    let mut files = HashMap::new();
+
+    for file_tuple in files_vec {
+      files.insert(file_tuple.0, file_tuple.1);
+    }
+
+    Box::new(Self { files })
+  }
+}
+
+impl DocFileLoader for TestLoader {
+  fn load_source_code(
+    &self,
+    specifier: &str,
+  ) -> Pin<Box<dyn Future<Output = Result<String, OpError>>>> {
+    eprintln!("specifier {:#?}", specifier);
+    let res = match self.files.get(specifier) {
+      Some(source_code) => Ok(source_code.to_string()),
+      None => Err(OpError::other("not found".to_string())),
+    };
+
+    async move { res }.boxed_local()
+  }
+}
+
+#[tokio::test]
+async fn export_fn() {
   let source_code = r#"/**
 * Hello there, this is a multiline JSdoc.
 *
@@ -17,9 +56,9 @@ export function foo(a: string, b: number): void {
     console.log("Hello world");
 }
 "#;
-  let entries = DocParser::default()
-    .parse("test.ts".to_string(), source_code.to_string())
-    .unwrap();
+  let loader =
+    TestLoader::new(vec![("test.ts".to_string(), source_code.to_string())]);
+  let entries = DocParser::new(loader).parse("test.ts").await.unwrap();
   assert_eq!(entries.len(), 1);
   let entry = &entries[0];
   let expected_json = json!({
@@ -68,13 +107,13 @@ export function foo(a: string, b: number): void {
   );
 }
 
-#[test]
-fn export_const() {
+#[tokio::test]
+async fn export_const() {
   let source_code =
     "/** Something about fizzBuzz */\nexport const fizzBuzz = \"fizzBuzz\";\n";
-  let entries = DocParser::default()
-    .parse("test.ts".to_string(), source_code.to_string())
-    .unwrap();
+  let loader =
+    TestLoader::new(vec![("test.ts".to_string(), source_code.to_string())]);
+  let entries = DocParser::new(loader).parse("test.ts").await.unwrap();
   assert_eq!(entries.len(), 1);
   let entry = &entries[0];
   let expected_json = json!({
@@ -100,8 +139,8 @@ fn export_const() {
   );
 }
 
-#[test]
-fn export_class() {
+#[tokio::test]
+async fn export_class() {
   let source_code = r#"
 /** Class doc */
 export class Foobar extends Fizz implements Buzz, Aldrin {
@@ -124,9 +163,9 @@ export class Foobar extends Fizz implements Buzz, Aldrin {
     }
 }
 "#;
-  let entries = DocParser::default()
-    .parse("test.ts".to_string(), source_code.to_string())
-    .unwrap();
+  let loader =
+    TestLoader::new(vec![("test.ts".to_string(), source_code.to_string())]);
+  let entries = DocParser::new(loader).parse("test.ts").await.unwrap();
   assert_eq!(entries.len(), 1);
   let expected_json = json!({
     "kind": "class",
@@ -314,8 +353,8 @@ export class Foobar extends Fizz implements Buzz, Aldrin {
   );
 }
 
-#[test]
-fn export_interface() {
+#[tokio::test]
+async fn export_interface() {
   let source_code = r#"
 /**
  * Interface js doc
@@ -325,9 +364,9 @@ export interface Reader {
     read(buf: Uint8Array, something: unknown): Promise<number>
 }
     "#;
-  let entries = DocParser::default()
-    .parse("test.ts".to_string(), source_code.to_string())
-    .unwrap();
+  let loader =
+    TestLoader::new(vec![("test.ts".to_string(), source_code.to_string())]);
+  let entries = DocParser::new(loader).parse("test.ts").await.unwrap();
   assert_eq!(entries.len(), 1);
   let entry = &entries[0];
   let expected_json = json!({
@@ -399,15 +438,15 @@ export interface Reader {
   );
 }
 
-#[test]
-fn export_type_alias() {
+#[tokio::test]
+async fn export_type_alias() {
   let source_code = r#"
 /** Array holding numbers */
 export type NumberArray = Array<number>;
     "#;
-  let entries = DocParser::default()
-    .parse("test.ts".to_string(), source_code.to_string())
-    .unwrap();
+  let loader =
+    TestLoader::new(vec![("test.ts".to_string(), source_code.to_string())]);
+  let entries = DocParser::new(loader).parse("test.ts").await.unwrap();
   assert_eq!(entries.len(), 1);
   let entry = &entries[0];
   let expected_json = json!({
@@ -445,8 +484,8 @@ export type NumberArray = Array<number>;
   );
 }
 
-#[test]
-fn export_enum() {
+#[tokio::test]
+async fn export_enum() {
   let source_code = r#"
 /**
  * Some enum for good measure
@@ -457,9 +496,9 @@ export enum Hello {
     Buzz = "buzz",
 }
     "#;
-  let entries = DocParser::default()
-    .parse("test.ts".to_string(), source_code.to_string())
-    .unwrap();
+  let loader =
+    TestLoader::new(vec![("test.ts".to_string(), source_code.to_string())]);
+  let entries = DocParser::new(loader).parse("test.ts").await.unwrap();
   assert_eq!(entries.len(), 1);
   let entry = &entries[0];
   let expected_json = json!({
@@ -498,8 +537,8 @@ export enum Hello {
   );
 }
 
-#[test]
-fn export_namespace() {
+#[tokio::test]
+async fn export_namespace() {
   let source_code = r#"
 /** Namespace JSdoc */
 export namespace RootNs {
@@ -515,9 +554,9 @@ export namespace RootNs {
     }
 }
     "#;
-  let entries = DocParser::default()
-    .parse("test.ts".to_string(), source_code.to_string())
-    .unwrap();
+  let loader =
+    TestLoader::new(vec![("test.ts".to_string(), source_code.to_string())]);
+  let entries = DocParser::new(loader).parse("test.ts").await.unwrap();
   assert_eq!(entries.len(), 1);
   let entry = &entries[0];
   let expected_json = json!({
@@ -593,8 +632,8 @@ export namespace RootNs {
   );
 }
 
-#[test]
-fn declare_namespace() {
+#[tokio::test]
+async fn declare_namespace() {
   let source_code = r#"
 /** Namespace JSdoc */
 declare namespace RootNs {
@@ -610,9 +649,9 @@ declare namespace RootNs {
     }
 }
     "#;
-  let entries = DocParser::default()
-    .parse("test.ts".to_string(), source_code.to_string())
-    .unwrap();
+  let loader =
+    TestLoader::new(vec![("test.ts".to_string(), source_code.to_string())]);
+  let entries = DocParser::new(loader).parse("test.ts").await.unwrap();
   assert_eq!(entries.len(), 1);
   let entry = &entries[0];
   let expected_json = json!({
@@ -687,16 +726,16 @@ declare namespace RootNs {
       .contains("namespace RootNs")
   );
 }
-#[test]
-fn optional_return_type() {
+#[tokio::test]
+async fn optional_return_type() {
   let source_code = r#"
   export function foo(a: number) {
     return a;
   }
     "#;
-  let entries = DocParser::default()
-    .parse("test.ts".to_string(), source_code.to_string())
-    .unwrap();
+  let loader =
+    TestLoader::new(vec![("test.ts".to_string(), source_code.to_string())]);
+  let entries = DocParser::new(loader).parse("test.ts").await.unwrap();
   assert_eq!(entries.len(), 1);
   let entry = &entries[0];
   let expected_json = json!({
@@ -732,3 +771,94 @@ fn optional_return_type() {
       .contains("function foo(a: number)")
   );
 }
+
+#[tokio::test]
+async fn reexports() {
+  let nested_reexport_source_code = r#"
+/**
+  * JSDoc for bar
+  */
+export const bar = "bar";
+"#;
+  let reexport_source_code = r#"
+import { bar } from "./nested_reexport.ts";
+
+/**
+ * JSDoc for const
+ */
+export const foo = "foo";
+"#;
+  let test_source_code = r#"
+export { foo as fooConst } from "./reexport.ts";
+
+/** JSDoc for function */
+export function fooFn(a: number) {
+  return a;
+}
+"#;
+  let loader = TestLoader::new(vec![
+    ("file:///test.ts".to_string(), test_source_code.to_string()),
+    (
+      "file:///reexport.ts".to_string(),
+      reexport_source_code.to_string(),
+    ),
+    (
+      "file:///nested_reexport.ts".to_string(),
+      nested_reexport_source_code.to_string(),
+    ),
+  ]);
+  let entries = DocParser::new(loader)
+    .parse_with_reexports("file:///test.ts")
+    .await
+    .unwrap();
+  assert_eq!(entries.len(), 2);
+
+  let expected_json = json!([
+    {
+      "kind": "variable",
+      "name": "fooConst",
+      "location": {
+        "filename": "file:///reexport.ts",
+        "line": 7,
+        "col": 0
+      },
+      "jsDoc": "JSDoc for const",
+      "variableDef": {
+        "tsType": null,
+        "kind": "const"
+      }
+    },
+    {
+      "kind": "function",
+      "name": "fooFn",
+      "location": {
+        "filename": "file:///test.ts",
+        "line": 5,
+        "col": 0
+      },
+      "jsDoc": "JSDoc for function",
+      "functionDef": {
+        "params": [
+            {
+              "name": "a",
+              "tsType": {
+                "keyword": "number",
+                "kind": "keyword",
+                "repr": "number",
+              },
+            }
+        ],
+        "returnType": null,
+        "isAsync": false,
+        "isGenerator": false
+      }
+    }
+  ]);
+  let actual = serde_json::to_value(entries.clone()).unwrap();
+  assert_eq!(actual, expected_json);
+
+  assert!(
+    colors::strip_ansi_codes(super::printer::format(entries).as_str())
+      .contains("function fooFn(a: number)")
+  );
+}
diff --git a/cli/lib.rs b/cli/lib.rs
index 9ccc8d022..a87846c11 100644
--- a/cli/lib.rs
+++ b/cli/lib.rs
@@ -66,9 +66,12 @@ pub use dprint_plugin_typescript::swc_ecma_ast;
 pub use dprint_plugin_typescript::swc_ecma_parser;
 
 use crate::compilers::TargetLib;
+use crate::doc::parser::DocFileLoader;
 use crate::file_fetcher::SourceFile;
+use crate::file_fetcher::SourceFileFetcher;
 use crate::global_state::GlobalState;
 use crate::msg::MediaType;
+use crate::op_error::OpError;
 use crate::ops::io::get_stdio;
 use crate::state::DebugType;
 use crate::state::State;
@@ -79,12 +82,14 @@ use deno_core::ModuleSpecifier;
 use flags::DenoSubcommand;
 use flags::Flags;
 use futures::future::FutureExt;
+use futures::Future;
 use log::Level;
 use log::Metadata;
 use log::Record;
 use std::env;
 use std::io::Write;
 use std::path::PathBuf;
+use std::pin::Pin;
 use upgrade::upgrade_command;
 use url::Url;
 
@@ -371,24 +376,35 @@ async fn doc_command(
   let global_state = GlobalState::new(flags.clone())?;
   let module_specifier =
     ModuleSpecifier::resolve_url_or_path(&source_file).unwrap();
-  let source_file = global_state
-    .file_fetcher
-    .fetch_source_file(&module_specifier, None)
-    .await?;
-  let source_code = String::from_utf8(source_file.source_code)?;
 
-  let doc_parser = doc::DocParser::default();
-  let parse_result =
-    doc_parser.parse(module_specifier.to_string(), source_code);
+  impl DocFileLoader for SourceFileFetcher {
+    fn load_source_code(
+      &self,
+      specifier: &str,
+    ) -> Pin<Box<dyn Future<Output = Result<String, OpError>>>> {
+      let specifier =
+        ModuleSpecifier::resolve_url_or_path(specifier).expect("Bad specifier");
+      let fetcher = self.clone();
+
+      async move {
+        let source_file = fetcher.fetch_source_file(&specifier, None).await?;
+        String::from_utf8(source_file.source_code)
+          .map_err(|_| OpError::other("failed to parse".to_string()))
+      }
+      .boxed_local()
+    }
+  }
+
+  let loader = Box::new(global_state.file_fetcher.clone());
+  let doc_parser = doc::DocParser::new(loader);
+  let parse_result = doc_parser
+    .parse_with_reexports(&module_specifier.to_string())
+    .await;
 
   let doc_nodes = match parse_result {
     Ok(nodes) => nodes,
     Err(e) => {
-      eprintln!("Failed to parse documentation:");
-      for diagnostic in e {
-        eprintln!("{}", diagnostic.message());
-      }
-
+      eprintln!("{}", e);
       std::process::exit(1);
     }
   };