diff --git a/addons/source-map.js b/addons/source-map.js
index b661a82d7b..bd640f39db 100644
--- a/addons/source-map.js
+++ b/addons/source-map.js
@@ -2,15 +2,26 @@ import { alterFile, revertFile } from "../lib/utils.js";
 
 export const args = ["--devtool", "source-map"];
 
-export const setup = async (options) => {
+export const setup = async () => {
 	await alterFile("tsconfig.json", (content) => {
-		return (
-			content &&
-			content.replace(/("compilerOptions": \{)/, '$1\n    "sourceMap": true,')
-		);
+		if (typeof content !== "string") return content;
+
+		try {
+			const tsconfig = JSON.parse(content);
+			tsconfig.compilerOptions = tsconfig.compilerOptions || {};
+			tsconfig.compilerOptions.sourceMap = true;
+			return JSON.stringify(tsconfig, null, 2) + "\n";
+		} catch {
+			// Fallback if JSON parsing fails
+			return content.replace(
+				/("compilerOptions"\s*:\s*\{)/,
+				'$1\n    "sourceMap": true,'
+			);
+		}
 	});
 };
 
-export const teardown = async (options) => {
+export const teardown = async () => {
+	// Restore original tsconfig.json
 	await revertFile("tsconfig.json");
 };