Repository: nodejs/node
Pull request: tty: use terminal VT mode on Windows

As of 0315283cbd, the libuv `UV_TTY_MODE_RAW_VT` flag is available for applications on Windows in order to have the terminal itself translate keypresses into control sequences, rather than libuv. This aligns the TTY setup more closely with POSIX platforms, and enables handling of control sequences in applications which libuv is not able to emit at all.

Since the Node.js `readline` implementation already handles divergences between different control character sequences for the same keypresses (e.g. `<ESC>[[A` vs `<ESC>OP` for the F1 key), this should not present a visible change for typical Node.js TTY applications.

Testing is handled on the libuv side, and not easily feasible with Node.js’s current TTY test setup.

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Changed files:
filename: src/tty_wrap.cc
patch: @@ -116,7 +116,17 @@ void TTYWrap::SetRawMode(const FunctionCallbackInfo<Value>& args) {
   TTYWrap* wrap;
   ASSIGN_OR_RETURN_UNWRAP(
       &wrap, args.This(), args.GetReturnValue().Set(UV_EBADF));
-  int err = uv_tty_set_mode(&wrap->handle_, args[0]->IsTrue());
+  // UV_TTY_MODE_RAW_VT is a variant of UV_TTY_MODE_RAW that
+  // enables control sequence processing on the TTY implementer side,
+  // rather than having libuv translate keypress events into
+  // control sequences, aligning behavior more closely with
+  // POSIX platforms. This is also required to support some control
+  // sequences at all on Windows, such as bracketed paste mode.
+  // The Node.js readline implementation handles differences between
+  // these modes.
+  int err = uv_tty_set_mode(
+      &wrap->handle_,
+      args[0]->IsTrue() ? UV_TTY_MODE_RAW_VT : UV_TTY_MODE_NORMAL);
   args.GetReturnValue().Set(err);
 }