wip: redesign csr: feat: impl RenderInitPinned for array

Author: EqualMa

packages/frender-common/src/reactive_value.rs

@@ -2,6 +2,7 @@ use std::{pin::Pin, task::Poll};
 
 use crate::csr::StateUnmount;
 
+mod array;
 pub mod csr_str;
 pub mod simple_non_reactive;
 

packages/frender-common/src/reactive_value/array.rs

@@ -0,0 +1,25 @@
+use frender_pin_utils::pin_project_iter_mut_array;
+
+use super::RenderInitPinned;
+
+impl<
+        T: for<'r> RenderInitPinned<&'r mut R, S, Output = Out>,
+        const N: usize,
+        R: ?Sized,
+        S,
+        Out,
+    > RenderInitPinned<&mut R, [S; N]> for [T; N]
+{
+    type Output = [Out; N];
+
+    fn render_init_pinned(
+        self,
+        renderer: &mut R,
+        state: std::pin::Pin<&mut [S; N]>,
+    ) -> Self::Output {
+        let mut state = pin_project_iter_mut_array(state);
+        // This relies on a documented feature of <[_; N]>::map():
+        // > ..., with function f applied to each element in order
+        self.map(|this| this.render_init_pinned(renderer, state.next().unwrap()))
+    }
+}