Trim UTF8 buffer to size after encoding

geraintluff · geraintluff · commit 5d54b3c0c7c6 · 2026-01-15T09:57:25.000Z
diff --git a/src/builtins.ts b/src/builtins.ts
@@ -3524,7 +3524,9 @@ function utf16ToUtf8(str: string) : Uint8Array {
       result[utf8Length++] = 0x80 + (codePoint&0x3F);
     }
   }
-  return result.subarray(0, utf8Length);
+  let trimmed = new Uint8Array(utf8Length);
+  for (let i: i32 = 0; i < utf8Length; ++i) trimmed[i] = result[i];
+  return trimmed;
 }
 
 // memory.dataUTF8(value) -> usize

Original file line number	Diff line number	Diff line change
`@@ -3524,7 +3524,9 @@ function utf16ToUtf8(str: string) : Uint8Array {`
`3524`	`3524`	`result[utf8Length++] = 0x80 + (codePoint&0x3F);`
`3525`	`3525`	`}`
`3526`	`3526`	`}`
`3527`		`- return result.subarray(0, utf8Length);`
	`3527`	`+ let trimmed = new Uint8Array(utf8Length);`
	`3528`	`+ for (let i: i32 = 0; i < utf8Length; ++i) trimmed[i] = result[i];`
	`3529`	`+ return trimmed;`
`3528`	`3530`	`}`
`3529`	`3531`
`3530`	`3532`	`// memory.dataUTF8(value) -> usize`