diff --git a/package.json b/package.json
index ecd3b1c3..8ac0d689 100644
--- a/package.json
+++ b/package.json
@@ -50,5 +50,8 @@
   },
   "peerDependencies": {
     "vue": "^3.2.13"
+  },
+  "dependencies": {
+    "fflate": "^0.7.3"
   }
 }
diff --git a/pnpm-lock.yaml b/pnpm-lock.yaml
index ab926bf1..f4fff07e 100644
--- a/pnpm-lock.yaml
+++ b/pnpm-lock.yaml
@@ -7,6 +7,7 @@ specifiers:
   '@types/node': ^16.11.12
   '@vitejs/plugin-vue': ^1.9.0
   codemirror: ^5.62.3
+  fflate: ^0.7.3
   hash-sum: ^2.0.0
   rimraf: ^3.0.2
   sucrase: ^3.20.1
@@ -15,6 +16,9 @@ specifiers:
   vue: ^3.2.36
   vue-tsc: ^0.34.15
 
+dependencies:
+  fflate: 0.7.3
+
 devDependencies:
   '@babel/types': 7.17.12
   '@microsoft/api-extractor': 7.24.0
@@ -608,6 +612,10 @@ packages:
     resolution: {integrity: sha512-lhd/wF+Lk98HZoTCtlVraHtfh5XYijIjalXck7saUtuanSDyLMxnHhSXEDJqHxD7msR8D0uCmqlkwjCV8xvwHw==}
     dev: true
 
+  /fflate/0.7.3:
+    resolution: {integrity: sha512-0Zz1jOzJWERhyhsimS54VTqOteCNwRtIlh8isdL0AXLo0g7xNTfTL7oWrkmCnPhZGocKIkWHBistBrrpoNH3aw==}
+    dev: false
+
   /fs-extra/7.0.1:
     resolution: {integrity: sha512-YJDaCJZEnBmcbw13fvdAM9AwNOJwOzrE4pqMqBq5nFiEqXUqHwlK4B+3pUw6JNvfSPtX05xFHtYy/1ni01eGCw==}
     engines: {node: '>=6 <7 || >=8'}
diff --git a/src/utils.ts b/src/utils.ts
index bfc6d708..fd458862 100644
--- a/src/utils.ts
+++ b/src/utils.ts
@@ -1,3 +1,5 @@
+import { zlibSync, unzlibSync, strToU8, strFromU8 } from 'fflate'
+
 export function debounce(fn: Function, n = 100) {
   let handle: any
   return (...args: any[]) => {
@@ -8,12 +10,24 @@ export function debounce(fn: Function, n = 100) {
   }
 }
 
-// prefer old unicode hacks for backward compatibility
-// https://base64.guru/developers/javascript/examples/unicode-strings
 export function utoa(data: string): string {
-  return btoa(unescape(encodeURIComponent(data)))
+  const buffer = strToU8(data)
+  const zipped = zlibSync(buffer, { level: 9 })
+  const binary = strFromU8(zipped, true)
+  return btoa(binary)
 }
 
 export function atou(base64: string): string {
-  return decodeURIComponent(escape(atob(base64)))
+  const binary = atob(base64)
+
+  // zlib header (x78), level 9 (xDA)
+  if (binary.startsWith('\x78\xDA')) {
+    const buffer = strToU8(binary, true)
+    const unzipped = unzlibSync(buffer)
+    return strFromU8(unzipped)
+  }
+
+  // old unicode hacks for backward compatibility
+  // https://base64.guru/developers/javascript/examples/unicode-strings
+  return decodeURIComponent(escape(binary))
 }