Make if and each blocks reactive on the client

packages/csr/test/reactive.test.ts

@@ -117,6 +117,55 @@ test("@event (data-on-click) mutates a signal and re-renders", () => {
   expect(btn.textContent).toBe("2");
 });
 
+test("compiled if blocks switch branches after hydration", () => {
+  const definition = Buffer.from(
+    JSON.stringify([
+      { cond: "open", body: '<p class="open">Open <span data-text="count">{count}</span></p>' },
+      { cond: null, body: '<p class="closed">Closed</p>' },
+    ]),
+  ).toString("base64");
+  const win = mount(
+    `<div data-scope="open: false, count: 2">` +
+      `<button data-on-click="open = !open">toggle</button>` +
+      `<button data-on-click="count++">increment</button>` +
+      `<template data-wrn-if="${definition}"></template><p class="closed">Closed</p><template data-wrn-control-end></template>` +
+      `</div>`,
+  );
+
+  win.document.querySelector("button")!.click();
+  expect(win.document.querySelector(".closed")).toBeNull();
+  expect(win.document.querySelector(".open")?.textContent).toBe("Open 2");
+  win.document.querySelectorAll("button")[1]!.click();
+  expect(win.document.querySelector(".open")?.textContent).toBe("Open 3");
+});
+
+test("compiled each blocks rerender rows and their empty branch", () => {
+  const definition = Buffer.from(
+    JSON.stringify({
+      list: "items",
+      item: "item",
+      index: "index",
+      body: '<p class="row">{index}:{item}</p>',
+      empty: '<p class="empty">Empty</p>',
+    }),
+  ).toString("base64");
+  const win = mount(
+    `<div data-scope="items: ['a']">` +
+      `<button data-on-click="items = ['b', 'c']">more</button>` +
+      `<button data-on-click="items = []">clear</button>` +
+      `<template data-wrn-each="${definition}"></template><p class="row">0:a</p><template data-wrn-control-end></template>` +
+      `</div>`,
+  );
+
+  win.document.querySelectorAll("button")[0]!.click();
+  expect(Array.from(win.document.querySelectorAll(".row")).map((node) => node.textContent)).toEqual(
+    ["0:b", "1:c"],
+  );
+  win.document.querySelectorAll("button")[1]!.click();
+  expect(win.document.querySelector(".row")).toBeNull();
+  expect(win.document.querySelector(".empty")?.textContent).toBe("Empty");
+});
+
 test("component functions support formatted multiline assignments and ternaries", () => {
   const behavior = Buffer.from(
     JSON.stringify({