From 41b48e53bb100b1496cbdd53c82f6c7f556a81f4 Mon Sep 17 00:00:00 2001
From: Hayleigh Thompson <me@hayleigh.dev>
Date: Wed, 19 Jun 2024 08:56:54 +0100
Subject: :recycle: Adopt component styles by copying page <link> and <style>
 tags.

---
 src/server-component.mjs | 34 ++++++++++++++++++++++++++++++----
 src/vdom.ffi.mjs         | 16 +++++++++-------
 2 files changed, 39 insertions(+), 11 deletions(-)

diff --git a/src/server-component.mjs b/src/server-component.mjs
index d4cb4a9..855ff9d 100644
--- a/src/server-component.mjs
+++ b/src/server-component.mjs
@@ -19,6 +19,7 @@ export class LustreServerComponent extends HTMLElement {
   #root = null;
   #socket = null;
   #shadow = null;
+  #stylesOffset = 0;
 
   constructor() {
     super();
@@ -52,11 +53,13 @@ export class LustreServerComponent extends HTMLElement {
     for (const link of document.querySelectorAll("link")) {
       if (link.rel === "stylesheet") {
         this.#shadow.appendChild(link.cloneNode(true));
+        this.#stylesOffset++;
       }
     }
 
     for (const style of document.querySelectorAll("style")) {
       this.#shadow.appendChild(style.cloneNode(true));
+      this.#stylesOffset++;
     }
 
     this.#root = document.createElement("div");
@@ -152,16 +155,27 @@ export class LustreServerComponent extends HTMLElement {
 
   morph(vdom) {
     this.#root = morph(this.#root, vdom, (handler) => (event) => {
+      const data = JSON.parse(this.getAttribute("data-lustre-data") || "{}");
       const msg = handler(event);
+
+      msg.data = merge(data, msg.data);
+
       this.#socket?.send(JSON.stringify([Constants.event, msg.tag, msg.data]));
     });
   }
 
   diff([diff]) {
-    this.#root = patch(this.#root, diff, (handler) => (event) => {
-      const msg = handler(event);
-      this.#socket?.send(JSON.stringify([Constants.event, msg.tag, msg.data]));
-    });
+    this.#root = patch(
+      this.#root,
+      diff,
+      (handler) => (event) => {
+        const msg = handler(event);
+        this.#socket?.send(
+          JSON.stringify([Constants.event, msg.tag, msg.data]),
+        );
+      },
+      this.#stylesOffset,
+    );
   }
 
   emit([event, data]) {
@@ -182,3 +196,15 @@ export class LustreServerComponent extends HTMLElement {
 }
 
 window.customElements.define("lustre-server-component", LustreServerComponent);
+
+// UTILS -----------------------------------------------------------------------
+
+function merge(target, source) {
+  for (const key in source) {
+    if (source[key] instanceof Object)
+      Object.assign(source[key], merge(target[key], source[key]));
+  }
+
+  Object.assign(target || {}, source);
+  return target;
+}
diff --git a/src/vdom.ffi.mjs b/src/vdom.ffi.mjs
index c3d12e2..0c645c1 100644
--- a/src/vdom.ffi.mjs
+++ b/src/vdom.ffi.mjs
@@ -84,7 +84,7 @@ export function morph(prev, next, dispatch, isComponent = false) {
   return out;
 }
 
-export function patch(root, diff, dispatch) {
+export function patch(root, diff, dispatch, stylesOffset = 0) {
   const rootParent = root.parentNode;
 
   // A diff is a tuple of three arrays: created, removed, updated. Each of these
@@ -101,7 +101,7 @@ export function patch(root, diff, dispatch) {
   for (const created of diff[0]) {
     const key = created[0].split("-");
     const next = created[1];
-    const prev = getDeepChild(rootParent, key);
+    const prev = getDeepChild(rootParent, key, stylesOffset);
 
     let result;
 
@@ -113,7 +113,7 @@ export function patch(root, diff, dispatch) {
     // tree. This can happen because we might get a patch that tells us some node
     // was created at a path that doesn't exist yet.
     else {
-      const parent = getDeepChild(rootParent, key.slice(0, -1));
+      const parent = getDeepChild(rootParent, key.slice(0, -1), stylesOffset);
       const temp = document.createTextNode("");
       parent.appendChild(temp);
       result = morph(temp, next, dispatch);
@@ -130,7 +130,7 @@ export function patch(root, diff, dispatch) {
   // the removed element.
   for (const removed of diff[1]) {
     const key = removed[0].split("-");
-    const deletedNode = getDeepChild(rootParent, key);
+    const deletedNode = getDeepChild(rootParent, key, stylesOffset);
     deletedNode.remove();
   }
 
@@ -139,7 +139,7 @@ export function patch(root, diff, dispatch) {
   for (const updated of diff[2]) {
     const key = updated[0].split("-");
     const patches = updated[1];
-    const prev = getDeepChild(rootParent, key);
+    const prev = getDeepChild(rootParent, key, stylesOffset);
     const handlersForEl = registeredHandlers.get(prev);
 
     for (const created of patches[0]) {
@@ -455,13 +455,15 @@ function getKeyedChildren(el) {
   return keyedChildren;
 }
 
-function getDeepChild(el, path) {
+function getDeepChild(el, path, stylesOffset) {
   let n;
   let rest;
   let child = el;
+  let isFirstInPath = true;
 
   while ((([n, ...rest] = path), n !== undefined)) {
-    child = child.childNodes.item(n);
+    child = child.childNodes.item(isFirstInPath ? n + stylesOffset : n);
+    isFirstInPath = false;
     path = rest;
   }
 
-- 
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