From ba1e67844e268700406f81188c36d673d6339f35 Mon Sep 17 00:00:00 2001
From: gtmnayan <50981692+gtm-nayan@users.noreply.github.com>
Date: Sun, 20 Aug 2023 16:19:32 +0545
Subject: [PATCH] fix: css sourcemap generation with unicode filenames (#9120)

* fix: css sourcemap generation with unicode filenames

* format
---
 .changeset/eighty-poems-deliver.md                |  5 +++++
 packages/svelte/src/compiler/utils/mapped_code.js | 13 ++++++++++++-
 2 files changed, 17 insertions(+), 1 deletion(-)
 create mode 100644 .changeset/eighty-poems-deliver.md

diff --git a/.changeset/eighty-poems-deliver.md b/.changeset/eighty-poems-deliver.md
new file mode 100644
index 0000000000..a209b85bd4
--- /dev/null
+++ b/.changeset/eighty-poems-deliver.md
@@ -0,0 +1,5 @@
+---
+'svelte': patch
+---
+
+fix: css sourcemap generation with unicode filenames
diff --git a/packages/svelte/src/compiler/utils/mapped_code.js b/packages/svelte/src/compiler/utils/mapped_code.js
index 0987b85ada..22645dd44b 100644
--- a/packages/svelte/src/compiler/utils/mapped_code.js
+++ b/packages/svelte/src/compiler/utils/mapped_code.js
@@ -292,7 +292,18 @@ export function apply_preprocessor_sourcemap(filename, svelte_map, preprocessor_
 		toUrl: {
 			enumerable: false,
 			value: function toUrl() {
-				return 'data:application/json;charset=utf-8;base64,' + btoa(this.toString());
+				let b64 = '';
+				if (typeof window !== 'undefined' && window.btoa) {
+					// btoa doesn't support multi-byte characters
+					b64 = window.btoa(unescape(encodeURIComponent(this.toString())));
+				} else if (typeof Buffer !== 'undefined') {
+					b64 = Buffer.from(this.toString(), 'utf8').toString('base64');
+				} else {
+					throw new Error(
+						'Unsupported environment: `window.btoa` or `Buffer` should be present to use toUrl.'
+					);
+				}
+				return 'data:application/json;charset=utf-8;base64,' + b64;
 			}
 		}
 	});