diff --git a/index.js b/index.js
index 8987f90..fc06e13 100644
--- a/index.js
+++ b/index.js
@@ -8,15 +8,13 @@ const imageminSvgo = options => async buffer => {
 		...options,
 	};
 
-	if (!isSvg(buffer)) {
-		return buffer;
-	}
+	const normalizedInput = Buffer.isBuffer(buffer) ? buffer.toString() : buffer;
 
-	if (Buffer.isBuffer(buffer)) {
-		buffer = buffer.toString();
+	if (!isSvg(normalizedInput)) {
+		return buffer;
 	}
 
-	const {data} = optimize(buffer, options);
+	const {data} = optimize(normalizedInput, options);
 	return Buffer.from(data);
 };
 
diff --git a/package.json b/package.json
index 4ec6512..36dc190 100644
--- a/package.json
+++ b/package.json
@@ -28,11 +28,11 @@
 		"svgo"
 	],
 	"dependencies": {
-		"is-svg": "^5.0.0",
-		"svgo": "^3.2.0"
+		"is-svg": "^5.0.1",
+		"svgo": "^3.3.2"
 	},
 	"devDependencies": {
-		"ava": "^6.1.2",
+		"ava": "^6.1.3",
 		"xo": "^0.58.0"
 	}
 }