fix: stream ssr concat buffer first (#7830)

Author: keepview

.changeset/soft-plums-go.md

@@ -0,0 +1,6 @@
+---
+'@modern-js/runtime': patch
+---
+
+fix: stream ssr should concat buffer first, then stringify buffer
+fix: stream ssr 先拼接 buffer, 再将 buffer 处理成字符串

packages/runtime/plugin-runtime/src/core/server/stream/createReadableStream.ts

@@ -34,7 +34,7 @@ export const createReadableStreamFromElement: CreateReadableStreamFromElement =
 
     const sheet = new ServerStyleSheet();
 
-    const chunkVec: string[] = [];
+    const chunkVec: Buffer[] = [];
 
     const root = sheet.collectStyles(rootElement);
 
@@ -62,15 +62,19 @@ export const createReadableStreamFromElement: CreateReadableStreamFromElement =
               transform(chunk, _encoding, callback) {
                 try {
                   if (shellChunkStatus !== ShellChunkStatus.FINISH) {
-                    chunkVec.push(chunk.toString());
+                    chunkVec.push(
+                      Buffer.isBuffer(chunk) ? chunk : Buffer.from(chunk),
+                    );
                     /**
                      * The shell content of App may be splitted by multiple chunks to transform,
                      * when any node value's size is larger than the React limitation, refer to:
                      * https://github.com/facebook/react/blob/v18.2.0/packages/react-server/src/ReactServerStreamConfigNode.js#L53.
                      * So we use the `SHELL_STREAM_END_MARK` to mark the shell content' tail.
                      */
-                    let concatedChunk = chunkVec.join('');
-                    if (concatedChunk.includes(ESCAPED_SHELL_STREAM_END_MARK)) {
+                    const chunkStr = chunk.toString('utf-8');
+                    if (chunkStr.includes(ESCAPED_SHELL_STREAM_END_MARK)) {
+                      let concatedChunk =
+                        Buffer.concat(chunkVec).toString('utf-8');
                       concatedChunk = concatedChunk.replace(
                         ESCAPED_SHELL_STREAM_END_MARK,
                         '',