Add handling for bigint literals in default values

Ref: #2721

CHANGELOG.md

@@ -7,6 +7,7 @@
 ### Bug Fixes
 
 -   Correctly handle external link resolver link text when referencing an external symbol, #2700.
+-   Big integer literals are now supported as default values, #2721.
 -   Corrected handling of `@link` tags present in comments at the start of source files.
 
 ### Thanks!

src/lib/converter/convert-expression.ts

@@ -24,11 +24,18 @@ export function convertExpression(expression: ts.Expression): string {
         case ts.SyntaxKind.FalseKeyword:
         case ts.SyntaxKind.NullKeyword:
         case ts.SyntaxKind.NumericLiteral:
-        case ts.SyntaxKind.PrefixUnaryExpression:
+        case ts.SyntaxKind.BigIntLiteral:
         case ts.SyntaxKind.Identifier:
             return expression.getText();
     }
 
+    if (ts.isPrefixUnaryExpression(expression)) {
+        const inner = convertExpression(expression.operand);
+        if (inner != "...") {
+            return expression.getText();
+        }
+    }
+
     if (
         ts.isArrayLiteralExpression(expression) &&
         expression.elements.length === 0

src/test/converter2/issues/gh2721.ts

@@ -0,0 +1,3 @@
+export const big = 123n;
+
+export const neg = -123n;

src/test/issues.c2.test.ts

@@ -1780,4 +1780,10 @@ describe("Issue Tests", () => {
             { display: "resolver caption", target: "https://typedoc.org" },
         ]);
     });
+
+    it("#2721 handles bigint literals in default values", () => {
+        const project = convert();
+        equal(query(project, "big").defaultValue, "123n");
+        equal(query(project, "neg").defaultValue, "-123n");
+    });
 });