Add Drag & Drop for Visual Editing (#86)

* Add Drag & Drop for Visual Editing

* Update types and improve a few a couple small things surrounding page building

* Update next-sanity

nextjs-app/app/components/BlockRenderer.tsx

@@ -2,19 +2,22 @@ import React from "react";
 
 import Cta from "@/app/components/Cta";
 import Info from "@/app/components/InfoSection";
+import { dataAttr } from "@/sanity/lib/utils";
 
 type BlocksType = {
   [key: string]: React.FC<any>;
 };
 
 type BlockType = {
   _type: string;
-  _id: string;
+  _key: string;
 };
 
 type BlockProps = {
   index: number;
   block: BlockType;
+  pageId: string;
+  pageType: string;
 };
 
 const Blocks: BlocksType = {
@@ -25,14 +28,30 @@ const Blocks: BlocksType = {
 /**
  * Used by the <PageBuilder>, this component renders a the component that matches the block type.
  */
-export default function BlockRenderer({ block, index }: BlockProps) {
+export default function BlockRenderer({
+  block,
+  index,
+  pageId,
+  pageType,
+}: BlockProps) {
   // Block does exist
   if (typeof Blocks[block._type] !== "undefined") {
-    return React.createElement(Blocks[block._type], {
-      key: block._id,
-      block: block,
-      index: index,
-    });
+    return (
+      <div
+        key={block._key}
+        data-sanity={dataAttr({
+          id: pageId,
+          type: pageType,
+          path: `pageBuilder[_key=="${block._key}"]`,
+        }).toString()}
+      >
+        {React.createElement(Blocks[block._type], {
+          key: block._key,
+          block: block,
+          index: index,
+        })}
+      </div>
+    );
   }
   // Block doesn't exist yet
   return React.createElement(
@@ -41,6 +60,6 @@ export default function BlockRenderer({ block, index }: BlockProps) {
         A &ldquo;{block._type}&rdquo; block hasn&apos;t been created
       </div>
     ),
-    { key: block._id }
+    { key: block._key }
   );
 }

nextjs-app/app/components/PageBuilder.tsx

@@ -1,48 +1,105 @@
+"use client";
+
+import { SanityDocument } from "next-sanity";
+import { useOptimistic } from "next-sanity/hooks";
 import Link from "next/link";
 
 import BlockRenderer from "@/app/components/BlockRenderer";
 import { Page } from "@/sanity.types";
+import { dataAttr } from "@/sanity/lib/utils";
 import { studioUrl } from "@/sanity/lib/api";
 
 type PageBuilderPageProps = {
   page: Page;
 };
 
+type PageBuilderSection = {
+  _key: string;
+  _type: string;
+};
+
+type PageData = {
+  _id: string;
+  _type: string;
+  pageBuilder?: PageBuilderSection[];
+};
+
 /**
  * The PageBuilder component is used to render the blocks from the `pageBuilder` field in the Page type in your Sanity Studio.
  */
-export default function PageBuilder({ page }: PageBuilderPageProps) {
-  if (page?.pageBuilder && page.pageBuilder.length > 0) {
-    return (
-      <>
-        {page.pageBuilder.map((block: any, index: number) => (
-          <BlockRenderer key={block._key} index={index} block={block} />
-        ))}
-      </>
-    );
-  }
-
-  // If there are no blocks in the page builder.
+
+function renderSections(pageBuilderSections: PageBuilderSection[], page: Page) {
+  return (
+    <div
+      data-sanity={dataAttr({
+        id: page._id,
+        type: page._type,
+        path: `pageBuilder`,
+      }).toString()}
+    >
+      {pageBuilderSections.map((block: any, index: number) => (
+        <BlockRenderer
+          key={block._key}
+          index={index}
+          block={block}
+          pageId={page._id}
+          pageType={page._type}
+        />
+      ))}
+    </div>
+  );
+}
+
+function renderEmptyState(page: Page) {
   return (
-    <>
-      <div className="container">
-        <h1 className="text-4xl font-extrabold text-gray-900 tracking-tight sm:text-5xl">
-          This page has no content!
-        </h1>
-        <p className="mt-2 text-base text-gray-500">
-          Open the page in Sanity Studio to add content.
-        </p>
-        <div className="mt-10 flex">
-          <Link
-            className="rounded-full flex gap-2 mr-6 items-center bg-black hover:bg-red-500 focus:bg-cyan-500 py-3 px-6 text-white transition-colors duration-200"
-            href={`${studioUrl}/structure/intent/edit/template=page;type=page;path=pageBuilder;id=${page._id}`}
-            target="_blank"
-            rel="noopener noreferrer"
-          >
-            Add content to this page
-          </Link>
-        </div>
+    <div className="container">
+      <h1 className="text-4xl font-extrabold text-gray-900 tracking-tight sm:text-5xl">
+        This page has no content!
+      </h1>
+      <p className="mt-2 text-base text-gray-500">
+        Open the page in Sanity Studio to add content.
+      </p>
+      <div className="mt-10 flex">
+        <Link
+          className="rounded-full flex gap-2 mr-6 items-center bg-black hover:bg-red-500 focus:bg-cyan-500 py-3 px-6 text-white transition-colors duration-200"
+          href={`${studioUrl}/structure/intent/edit/template=page;type=page;path=pageBuilder;id=${page._id}`}
+          target="_blank"
+          rel="noopener noreferrer"
+        >
+          Add content to this page
+        </Link>
       </div>
-    </>
+    </div>
   );
 }
+
+export default function PageBuilder({ page }: PageBuilderPageProps) {
+  const pageBuilderSections = useOptimistic<
+    PageBuilderSection[] | undefined,
+    SanityDocument<PageData>
+  >(page?.pageBuilder, (currentSections, action) => {
+    // The action contains updated document data from Sanity
+    // when someone makes an edit in the Studio
+
+    // If the edit was to a different document, ignore it
+    if (action.id !== page._id) {
+      return currentSections;
+    }
+
+    // If there are sections in the updated document, use them
+    if (action.document.pageBuilder) {
+      // Reconcile References. https://www.sanity.io/docs/enabling-drag-and-drop#ffe728eea8c1
+      return action.document.pageBuilder.map(
+        (section) =>
+          currentSections?.find((s) => s._key === section?._key) || section
+      );
+    }
+
+    // Otherwise keep the current sections
+    return currentSections;
+  });
+
+  return pageBuilderSections && pageBuilderSections.length > 0
+    ? renderSections(pageBuilderSections, page)
+    : renderEmptyState(page);
+}