From dfed58a30fb9e3e38527d4fe76f839c848562d75 Mon Sep 17 00:00:00 2001
From: Gerrit Birkeland <gerrit@gerritbirkeland.com>
Date: Tue, 31 May 2022 20:24:07 -0600
Subject: [PATCH] Support for "declare global" modules

CC: @Zamiel
---
 CHANGELOG.md                                  |  4 ++++
 src/lib/converter/converter.ts                | 23 ++++++++++++++++++-
 src/test/behaviorTests.ts                     |  8 +++++++
 src/test/converter2/behavior/declareGlobal.ts |  9 ++++++++
 4 files changed, 43 insertions(+), 1 deletion(-)
 create mode 100644 src/test/converter2/behavior/declareGlobal.ts

diff --git a/CHANGELOG.md b/CHANGELOG.md
index bde708bd4..5747ea4c3 100644
--- a/CHANGELOG.md
+++ b/CHANGELOG.md
@@ -1,5 +1,9 @@
 # Unreleased
 
+### Features
+
+-   Added support for documenting a module's global declarations as its exports if it contains no real exports.
+
 ### Bug Fixes
 
 -   Restore support for TS 4.0 through 4.5, #1945.
diff --git a/src/lib/converter/converter.ts b/src/lib/converter/converter.ts
index 04f3d96c1..0b740d2bf 100644
--- a/src/lib/converter/converter.ts
+++ b/src/lib/converter/converter.ts
@@ -469,7 +469,7 @@ function getSymbolForModuleLike(
 
 function getExports(
     context: Context,
-    node: ts.SourceFile | ts.ModuleBlock,
+    node: ts.SourceFile,
     symbol: ts.Symbol | undefined
 ): ts.Symbol[] {
     let result: ts.Symbol[];
@@ -496,6 +496,27 @@ function getExports(
         result = context.checker
             .getExportsOfModule(symbol)
             .filter((s) => !hasAllFlags(s.flags, ts.SymbolFlags.Prototype));
+
+        if (result.length === 0) {
+            const globalDecl = node.statements.find(
+                (s) =>
+                    ts.isModuleDeclaration(s) &&
+                    s.flags & ts.NodeFlags.GlobalAugmentation
+            );
+
+            if (globalDecl) {
+                const globalSymbol = context.getSymbolAtLocation(globalDecl);
+                if (globalSymbol) {
+                    result = context.checker
+                        .getExportsOfModule(globalSymbol)
+                        .filter((exp) =>
+                            exp.declarations?.some(
+                                (d) => d.getSourceFile() === node
+                            )
+                        );
+                }
+            }
+        }
     } else {
         // Global file with no inferred top level symbol, get all symbols declared in this file.
         const sourceFile = node.getSourceFile();
diff --git a/src/test/behaviorTests.ts b/src/test/behaviorTests.ts
index 5f5179a77..2ad7ae0e6 100644
--- a/src/test/behaviorTests.ts
+++ b/src/test/behaviorTests.ts
@@ -81,6 +81,14 @@ export const behaviorTests: Record<
             "WithoutReadonlyNumeric"
         );
     },
+
+    declareGlobal(project) {
+        equal(
+            project.children?.map((c) => c.name),
+            ["DeclareGlobal"]
+        );
+    },
+
     duplicateHeritageClauses(project) {
         const b = query(project, "B");
         equal(b.extendedTypes?.map(String), ["A"]);
diff --git a/src/test/converter2/behavior/declareGlobal.ts b/src/test/converter2/behavior/declareGlobal.ts
new file mode 100644
index 000000000..c8f65e77a
--- /dev/null
+++ b/src/test/converter2/behavior/declareGlobal.ts
@@ -0,0 +1,9 @@
+import { SyntaxKind } from "typescript";
+
+declare global {
+    interface DeclareGlobal {
+        method(kind: SyntaxKind): void;
+    }
+}
+
+namespace NotIncluded {}