fix: Support JSDocNullableType, JSDocNonNullableType

Resolves #1524

Author: Gerrit0

src/lib/converter/types.ts

@@ -85,6 +85,9 @@ export function loadConverters() {
         tupleConverter,
         typeOperatorConverter,
         unionConverter,
+        // Only used if skipLibCheck: true
+        jsDocNullableTypeConverter,
+        jsDocNonNullableTypeConverter,
     ]) {
         for (const key of actor.kind) {
             if (key === undefined) {
@@ -986,6 +989,27 @@ const unionConverter: TypeConverter<ts.UnionTypeNode, ts.UnionType> = {
     },
 };
 
+const jsDocNullableTypeConverter: TypeConverter<ts.JSDocNullableType> = {
+    kind: [ts.SyntaxKind.JSDocNullableType],
+    convert(context, node) {
+        return new UnionType([
+            convertType(context, node.type),
+            new LiteralType(null),
+        ]);
+    },
+    // Should be a UnionType
+    convertType: requestBugReport,
+};
+
+const jsDocNonNullableTypeConverter: TypeConverter<ts.JSDocNonNullableType> = {
+    kind: [ts.SyntaxKind.JSDocNonNullableType],
+    convert(context, node) {
+        return convertType(context, node.type);
+    },
+    // Should be a UnionType
+    convertType: requestBugReport,
+};
+
 function requestBugReport(context: Context, nodeOrType: ts.Node | ts.Type) {
     if ("kind" in nodeOrType) {
         const kindName = ts.SyntaxKind[nodeOrType.kind];

src/test/converter/declaration/declaration.d.ts

@@ -3,3 +3,8 @@ export declare class Decl {
 }
 
 export declare const x: number;
+
+export namespace GH1524 {
+    export function nullable(opt: ?string): void;
+    export function nonNullable(opt: !string): void;
+}