Improve source structure in the node api (#6164)

* Update api/node/typescript/models.ts

Co-authored-by: Simon Hausmann <simon.hausmann@slint.dev>

* Code review feedback
---------

Co-authored-by: Simon Hausmann <simon.hausmann@slint.dev>

api/node/rust/lib.rs

@@ -0,0 +1,84 @@
+// Copyright © SixtyFPS GmbH <info@slint.dev>
+// SPDX-License-Identifier: GPL-3.0-only OR LicenseRef-Slint-Royalty-free-2.0 OR LicenseRef-Slint-Software-3.0
+
+mod interpreter;
+pub use interpreter::*;
+
+mod types;
+pub use types::*;
+
+use napi::{Env, JsFunction};
+
+#[macro_use]
+extern crate napi_derive;
+
+#[napi]
+pub fn mock_elapsed_time(ms: f64) {
+    i_slint_core::tests::slint_mock_elapsed_time(ms as _);
+}
+
+#[napi]
+pub fn get_mocked_time() -> f64 {
+    i_slint_core::tests::slint_get_mocked_time() as f64
+}
+
+#[napi]
+pub enum ProcessEventsResult {
+    Continue,
+    Exited,
+}
+
+#[napi]
+pub fn process_events() -> napi::Result<ProcessEventsResult> {
+    i_slint_backend_selector::with_platform(|b| {
+        b.process_events(std::time::Duration::ZERO, i_slint_core::InternalToken)
+    })
+    .map_err(|e| napi::Error::from_reason(e.to_string()))
+    .and_then(|result| {
+        Ok(match result {
+            core::ops::ControlFlow::Continue(()) => ProcessEventsResult::Continue,
+            core::ops::ControlFlow::Break(()) => ProcessEventsResult::Exited,
+        })
+    })
+}
+
+#[napi]
+pub fn invoke_from_event_loop(env: Env, callback: JsFunction) -> napi::Result<napi::JsUndefined> {
+    i_slint_backend_selector::with_platform(|_b| {
+        // Nothing to do, just make sure a backend was created
+        Ok(())
+    })
+    .map_err(|e| napi::Error::from_reason(e.to_string()))?;
+
+    let function_ref = RefCountedReference::new(&env, callback)?;
+    let function_ref = send_wrapper::SendWrapper::new(function_ref);
+    i_slint_core::api::invoke_from_event_loop(move || {
+        let function_ref = function_ref.take();
+        let callback: JsFunction = function_ref.get().unwrap();
+        callback.call_without_args(None).ok();
+    })
+    .map_err(|e| napi::Error::from_reason(e.to_string()))
+    .and_then(|_| env.get_undefined())
+}
+
+#[napi]
+pub fn set_quit_on_last_window_closed(
+    env: Env,
+    quit_on_last_window_closed: bool,
+) -> napi::Result<napi::JsUndefined> {
+    if !quit_on_last_window_closed {
+        i_slint_backend_selector::with_platform(|b| {
+            #[allow(deprecated)]
+            b.set_event_loop_quit_on_last_window_closed(false);
+            Ok(())
+        })
+        .map_err(|e| napi::Error::from_reason(e.to_string()))?;
+    }
+    env.get_undefined()
+}
+
+#[napi]
+pub fn init_testing() {
+    #[cfg(feature = "testing")]
+    i_slint_backend_testing::init_integration_test_with_mock_time();
+}