diff --git a/lib/rollup.config.js b/lib/rollup.config.js
index 8b6d5b70..8ef8f098 100644
--- a/lib/rollup.config.js
+++ b/lib/rollup.config.js
@@ -1,9 +1,16 @@
 import nodeResolve from "@rollup/plugin-node-resolve";
 import cleanup from 'rollup-plugin-cleanup';
 import sourcemaps from 'rollup-plugin-sourcemaps';
-import MagicString from 'magic-string';
+import MagicStringPkg from 'magic-string';
 
 const UglifyJs = require('uglify-js');
+// Handle both default-export and named/CommonJS export shapes across magic-string versions.
+let MagicString = MagicStringPkg;
+if (MagicStringPkg.default !== undefined) {
+    MagicString = MagicStringPkg.default;
+} else if (MagicStringPkg.MagicString !== undefined) {
+    MagicString = MagicStringPkg.MagicString;
+}
 
 const version = require("./package.json").version;
 const outputName = "ts-utils";
diff --git a/package.json b/package.json
index 533efdf2..4e2fea7a 100644
--- a/package.json
+++ b/package.json
@@ -279,7 +279,7 @@
         "karma-mocha": "^2.0.1",
         "karma-spec-reporter": "^0.0.36",
         "karma-typescript": "^5.5.4",
-        "magic-string": "^0.30.21",
+        "magic-string": "^1.0.0",
         "mocha": "^11.2.0",
         "nyc": "^18.0.0",
         "puppeteer": "^25.0.2",