[scramjet/core] fix charset encoding errors in worker rewriter

Author: velzie

packages/chrome/src/proxy/scramjet.ts

@@ -260,7 +260,9 @@ export function createFetchHandler(controller: Controller) {
 		return [
 			script(controller.prefix.href + virtualWasmPath),
 			script(controller.prefix.href + virtualInjectPath),
-			script("data:application/javascript;base64," + base64Encode(injected)),
+			script(
+				"data:text/javascript;charset=utf-8;base64," + base64Encode(injected)
+			),
 		];
 	};
 
@@ -284,7 +286,7 @@ export function createFetchHandler(controller: Controller) {
 		str += script(controller.prefix.href + virtualWasmPath);
 		str += script(controller.prefix.href + virtualInjectPath);
 		str += script(
-			`data:application/javascript;base64,${base64Encode(injectLoad)}`
+			`data:text/javascript;charset=utf-8;base64,${base64Encode(injectLoad)}`
 		);
 
 		return str;

packages/scramjet/packages/core/src/shared/rewriters/worker.ts

@@ -2,6 +2,18 @@ import { flagEnabled, ScramjetContext } from "@/shared";
 import { rewriteJs } from "@rewriters/js";
 import { URLMeta } from "@rewriters/url";
 
+function base64Encode(text: string) {
+	return btoa(
+		new TextEncoder()
+			.encode(text)
+			.reduce(
+				(data, byte) => (data.push(String.fromCharCode(byte)), data),
+				[] as any
+			)
+			.join("")
+	);
+}
+
 export function rewriteWorkers(
 	context: ScramjetContext,
 	js: string | Uint8Array,
@@ -16,7 +28,10 @@ export function rewriteWorkers(
 		}
 		return `importScripts("${script}");\n`;
 	};
+	const b64 = (script: string) =>
+		`data:text/javascript;charset=utf-8;base64,${base64Encode(script)}`;
 	let str = context.interface.getWorkerInjectScripts(meta, type, script);
+
 	let rewritten = rewriteJs(js, url, context, meta, module);
 	if (rewritten instanceof Uint8Array) {
 		rewritten = new TextDecoder().decode(rewritten);
@@ -25,10 +40,9 @@ export function rewriteWorkers(
 	if (flagEnabled("encapsulateWorkers", context, meta.origin)) {
 		// TODO: check if there's already a sourceURL/sourcemap before appending another?
 		rewritten += `//# sourceURL=${url}`;
-		str += script(`data:text/javascript;base64,${btoa(rewritten)}`);
+		str += script(b64(rewritten));
 	} else {
 		str += rewritten;
 	}
-
 	return str;
 }