JS: Fix encoding conversion from utf16 to utf8 (#131)

js/embed/pre.js

@@ -1,47 +1,52 @@
 var Module = {
-    stdinData: "",
-    stdoutCallback: null,
-    stderrCallback: null,
+    stdinData: null,
+    stdinDataPosition: 0,
+    stdoutData: [],
+    stderrData: [],
 
-    // Function to set a callback for stdout
-    setStdoutCallback: function(callback) {
-        this.stdoutCallback = callback;
+    // Function to read and return all collected stdout data as a string
+    readFromStdout: function() {
+        if (!this.stdoutData.length) return "";
+        const decoder = new TextDecoder('utf-8');
+        const data = decoder.decode(new Uint8Array(this.stdoutData));
+        this.stdoutData = [];
+        return data;
     },
 
-    // Function to set a callback for stderr
-    setStderrCallback: function(callback) {
-        this.stderrCallback = callback;
+    // Function to read and return all collected stderr data as a string
+    readFromStderr: function() {
+        if (!this.stderrData.length) return "";
+        const decoder = new TextDecoder('utf-8');
+        const data = decoder.decode(new Uint8Array(this.stderrData));
+        this.stderrData = [];
+        return data;
     },
 
     // Function to set input data for stdin
-    setStdinData: function(data) {
-        this.stdinData = data;
+    writeToStdin: function(data) {
+        const encoder = new TextEncoder();
+        this.stdinData = encoder.encode(data);
+        this.stdinDataPosition = 0;
     },
 
     // `preRun` is called before the program starts running
     preRun: function() {
         // Define a custom stdin function
         function customStdin() {
-            if (Module.stdinData.length === 0) {
+            if (!Module.stdinData || Module.stdinDataPosition >= Module.stdinData.length) {
                 return null; // End of input (EOF)
             }
-            const char = Module.stdinData.charCodeAt(0);
-            Module.stdinData = Module.stdinData.slice(1); // Remove the character from input
-            return char;
+            return Module.stdinData[Module.stdinDataPosition++];
         }
 
         // Define a custom stdout function
         function customStdout(char) {
-            if (Module.stdoutCallback) {
-                Module.stdoutCallback(String.fromCharCode(char));
-            }
+            Module.stdoutData.push(char);
         }
 
         // Define a custom stderr function
         function customStderr(char) {
-            if (Module.stderrCallback) {
-                Module.stderrCallback(String.fromCharCode(char));
-            }
+            Module.stderrData.push(char);
         }
 
         FS.init(customStdin, customStdout, customStderr);