Merge static and dynamic styles (#3950)

* Merge static and dynamic styles

---------

Co-authored-by: Jonathan Kelley <[email protected]>

Author: ealmloff

packages/interpreter/src/js/common.js

@@ -1 +1 @@
-[6449103750905854967, 17669692872757955279, 13069001215487072322, 11420464406527728232, 3770103091118609057, 5444526391971481782, 15100726369461302769, 5052021921702764563, 10988859153374944111, 16153602427306015669]
+[6449103750905854967, 17669692872757955279, 13069001215487072322, 11420464406527728232, 3770103091118609057, 5444526391971481782, 15100726369461302769, 5052021921702764563, 10988859153374944111, 8086017882241405700]

packages/interpreter/src/js/core.js

@@ -58,6 +58,25 @@ export function setAttributeInner(
       node.innerHTML = value;
       break;
 
+    case "style":
+      // Save the existing styles
+      const existingStyles: Record<string, string> = {};
+
+      for (let i = 0; i < node.style.length; i++) {
+        const prop = node.style[i];
+        existingStyles[prop] = node.style.getPropertyValue(prop);
+      }
+      // Override all styles
+      node.setAttribute(field, value);
+      // Restore the old styles
+      for (const prop in existingStyles) {
+        // If it wasn't overridden, restore it
+        if (!node.style.getPropertyValue(prop)) {
+          node.style.setProperty(prop, existingStyles[prop]);
+        }
+      }
+      break;
+
     case "multiple":
       setAttributeDefault(node, field, value);
       // reset the selected value whenever multiple changes

packages/interpreter/src/js/hash.txt

@@ -156,6 +156,16 @@ test("document elements", async ({ page }) => {
   await expect(main).toHaveCSS("font-family", "Roboto");
 });
 
+test("merge styles", async ({ page }) => {
+  await page.goto("http://localhost:9999");
+  // wait until the div is mounted
+  const div = page.locator("div#merge-styles-div");
+  await div.waitFor({ state: "attached" });
+  await expect(div).toHaveCSS("background-color", "rgb(255, 0, 0)");
+  await expect(div).toHaveCSS("width", "100px");
+  await expect(div).toHaveCSS("height", "100px");
+});
+
 test("select multiple", async ({ page }) => {
   await page.goto("http://localhost:9999");
   // wait until the select element is mounted

packages/interpreter/src/ts/set_attribute.ts

@@ -63,6 +63,7 @@ fn app() -> Element {
         OnMounted {}
         WebSysClosure {}
         DocumentElements {}
+        MergeStyles {}
         SelectMultiple {}
     }
 }
@@ -156,6 +157,20 @@ fn DocumentElements() -> Element {
     }
 }
 
+// Regression test for https://github.com/DioxusLabs/dioxus/issues/3887
+#[component]
+fn MergeStyles() -> Element {
+    let px = 100;
+
+    rsx! {
+        div {
+            id: "merge-styles-div",
+            style: "width: {px}px; height: {px}px",
+            background_color: "red",
+        }
+    }
+}
+
 // Select elements have odd default behavior when you set the multiple attribute after mounting the element
 // Regression test for https://github.com/DioxusLabs/dioxus/issues/3185
 #[component]