From 4aafb1ed9e78717c20237adc11a9d2eae3ddeaa4 Mon Sep 17 00:00:00 2001
From: Andrew Kingston <andrew@kingston.dev>
Date: Thu, 14 Dec 2023 15:19:23 +0000
Subject: [PATCH] Massively improve performance of hovering components

---
 .../src/builderStore/store/frontend.js        | 17 +++++-
 .../[screenId]/_components/AppPreview.svelte  |  6 +-
 .../ComponentList/ComponentTree.svelte        | 17 ++----
 .../_components/ComponentList/index.svelte    | 55 ++++++-------------
 .../components/preview/HoverIndicator.svelte  |  8 +--
 packages/client/src/index.js                  |  4 +-
 packages/client/src/stores/builder.js         | 11 ----
 packages/client/src/stores/hover.js           | 25 +++++++++
 packages/client/src/stores/index.js           |  3 +
 .../controllers/static/templates/preview.hbs  |  2 -
 10 files changed, 74 insertions(+), 74 deletions(-)
 create mode 100644 packages/client/src/stores/hover.js

diff --git a/packages/builder/src/builderStore/store/frontend.js b/packages/builder/src/builderStore/store/frontend.js
index aaa0eb0184..061cd4c6b5 100644
--- a/packages/builder/src/builderStore/store/frontend.js
+++ b/packages/builder/src/builderStore/store/frontend.js
@@ -5,6 +5,7 @@ import {
   selectedComponent,
   screenHistoryStore,
   automationHistoryStore,
+  store,
 } from "builderStore"
 import {
   datasources,
@@ -85,7 +86,6 @@ const INITIAL_FRONTEND_STATE = {
   selectedScreenId: null,
   selectedComponentId: null,
   selectedLayoutId: null,
-  hoverComponentId: null,
 
   // Client state
   selectedComponentInstance: null,
@@ -93,6 +93,9 @@ const INITIAL_FRONTEND_STATE = {
   // Onboarding
   onboarding: false,
   tourNodes: null,
+
+  // UI state
+  hoveredComponentId: null,
 }
 
 export const getFrontendStore = () => {
@@ -1414,6 +1417,18 @@ export const getFrontendStore = () => {
           return state
         })
       },
+      hover: (componentId, notifyClient = true) => {
+        if (componentId === get(store).hoveredComponentId) {
+          return
+        }
+        store.update(state => {
+          state.hoveredComponentId = componentId
+          return state
+        })
+        if (notifyClient) {
+          store.actions.preview.sendEvent("hover-component", componentId)
+        }
+      },
     },
     links: {
       save: async (url, title) => {
diff --git a/packages/builder/src/pages/builder/app/[application]/design/[screenId]/_components/AppPreview.svelte b/packages/builder/src/pages/builder/app/[application]/design/[screenId]/_components/AppPreview.svelte
index 65ea172012..2127392bb9 100644
--- a/packages/builder/src/pages/builder/app/[application]/design/[screenId]/_components/AppPreview.svelte
+++ b/packages/builder/src/pages/builder/app/[application]/design/[screenId]/_components/AppPreview.svelte
@@ -36,14 +36,12 @@
 
   // Determine selected component ID
   $: selectedComponentId = $store.selectedComponentId
-  $: hoverComponentId = $store.hoverComponentId
 
   $: previewData = {
     appId: $store.appId,
     layout,
     screen,
     selectedComponentId,
-    hoverComponentId,
     theme: $store.theme,
     customTheme: $store.customTheme,
     previewDevice: $store.previewDevice,
@@ -119,8 +117,8 @@
       error = event.error || "An unknown error occurred"
     } else if (type === "select-component" && data.id) {
       $store.selectedComponentId = data.id
-    } else if (type === "hover-component" && data.id) {
-      $store.hoverComponentId = data.id
+    } else if (type === "hover-component") {
+      store.actions.components.hover(data.id, false)
     } else if (type === "update-prop") {
       await store.actions.components.updateSetting(data.prop, data.value)
     } else if (type === "update-styles") {
diff --git a/packages/builder/src/pages/builder/app/[application]/design/[screenId]/_components/ComponentList/ComponentTree.svelte b/packages/builder/src/pages/builder/app/[application]/design/[screenId]/_components/ComponentList/ComponentTree.svelte
index 8d4d64e4be..315c0a331e 100644
--- a/packages/builder/src/pages/builder/app/[application]/design/[screenId]/_components/ComponentList/ComponentTree.svelte
+++ b/packages/builder/src/pages/builder/app/[application]/design/[screenId]/_components/ComponentList/ComponentTree.svelte
@@ -90,16 +90,7 @@
     return findComponentPath($selectedComponent, component._id)?.length > 0
   }
 
-  const handleMouseover = componentId => {
-    if ($store.hoverComponentId !== componentId) {
-      $store.hoverComponentId = componentId
-    }
-  }
-  const handleMouseout = componentId => {
-    if ($store.hoverComponentId === componentId) {
-      $store.hoverComponentId = null
-    }
-  }
+  const hover = store.actions.components.hover
 </script>
 
 <ul>
@@ -120,9 +111,9 @@
         on:dragover={dragover(component, index)}
         on:iconClick={() => toggleNodeOpen(component._id)}
         on:drop={onDrop}
-        hovering={$store.hoverComponentId === component._id}
-        on:mouseenter={() => handleMouseover(component._id)}
-        on:mouseleave={() => handleMouseout(component._id)}
+        hovering={$store.hoveredComponentId === component._id}
+        on:mouseenter={() => hover(component._id)}
+        on:mouseleave={() => hover(null)}
         text={getComponentText(component)}
         icon={getComponentIcon(component)}
         iconTooltip={getComponentName(component)}
diff --git a/packages/builder/src/pages/builder/app/[application]/design/[screenId]/_components/ComponentList/index.svelte b/packages/builder/src/pages/builder/app/[application]/design/[screenId]/_components/ComponentList/index.svelte
index 1e2ea47e63..0f7e71255d 100644
--- a/packages/builder/src/pages/builder/app/[application]/design/[screenId]/_components/ComponentList/index.svelte
+++ b/packages/builder/src/pages/builder/app/[application]/design/[screenId]/_components/ComponentList/index.svelte
@@ -12,6 +12,9 @@
 
   let scrolling = false
 
+  $: screenComponentId = `${$store.selectedScreenId}-screen`
+  $: navComponentId = `${$store.selectedScreenId}-navigation`
+
   const toNewComponentRoute = () => {
     if ($isActive(`./:componentId/new`)) {
       $goto(`./:componentId`)
@@ -33,16 +36,7 @@
     scrolling = e.target.scrollTop !== 0
   }
 
-  const handleMouseover = componentId => {
-    if ($store.hoverComponentId !== componentId) {
-      $store.hoverComponentId = componentId
-    }
-  }
-  const handleMouseout = componentId => {
-    if ($store.hoverComponentId === componentId) {
-      $store.hoverComponentId = null
-    }
-  }
+  const hover = store.actions.components.hover
 </script>
 
 <div class="components">
@@ -65,46 +59,31 @@
             scrollable
             icon="WebPage"
             on:drop={onDrop}
-            on:click={() => {
-              $store.selectedComponentId = `${$store.selectedScreenId}-screen`
-            }}
-            hovering={$store.hoverComponentId ===
-              `${$store.selectedScreenId}-screen`}
-            on:mouseenter={() =>
-              handleMouseover(`${$store.selectedScreenId}-screen`)}
-            on:mouseleave={() =>
-              handleMouseout(`${$store.selectedScreenId}-screen`)}
-            id={`component-screen`}
-            selectedBy={$userSelectedResourceMap[
-              `${$store.selectedScreenId}-screen`
-            ]}
+            on:click={() => ($store.selectedComponentId = screenComponentId)}
+            hovering={$store.hoveredComponentId === screenComponentId}
+            on:mouseenter={() => hover(`${$store.selectedScreenId}-screen`)}
+            on:mouseleave={() => hover(null)}
+            id="component-screen"
+            selectedBy={$userSelectedResourceMap[screenComponentId]}
           >
             <ScreenslotDropdownMenu component={$selectedScreen?.props} />
           </NavItem>
           <NavItem
             text="Navigation"
             indentLevel={0}
-            selected={$store.selectedComponentId ===
-              `${$store.selectedScreenId}-navigation`}
+            selected={$store.selectedComponentId === navComponentId}
             opened
             scrollable
             icon={$selectedScreen.showNavigation
               ? "Visibility"
               : "VisibilityOff"}
             on:drop={onDrop}
-            on:click={() => {
-              $store.selectedComponentId = `${$store.selectedScreenId}-navigation`
-            }}
-            hovering={$store.hoverComponentId ===
-              `${$store.selectedScreenId}-navigation`}
-            on:mouseenter={() =>
-              handleMouseover(`${$store.selectedScreenId}-navigation`)}
-            on:mouseleave={() =>
-              handleMouseout(`${$store.selectedScreenId}-navigation`)}
-            id={`component-nav`}
-            selectedBy={$userSelectedResourceMap[
-              `${$store.selectedScreenId}-navigation`
-            ]}
+            on:click={() => ($store.selectedComponentId = navComponentId)}
+            hovering={$store.hoveredComponentId === navComponentId}
+            on:mouseenter={() => hover(navComponentId)}
+            on:mouseleave={() => hover(null)}
+            id="component-nav"
+            selectedBy={$userSelectedResourceMap[navComponentId]}
           />
           <ComponentTree
             level={0}
diff --git a/packages/client/src/components/preview/HoverIndicator.svelte b/packages/client/src/components/preview/HoverIndicator.svelte
index ddef62ab74..164ec32ab4 100644
--- a/packages/client/src/components/preview/HoverIndicator.svelte
+++ b/packages/client/src/components/preview/HoverIndicator.svelte
@@ -1,9 +1,9 @@
 <script>
   import { onMount, onDestroy } from "svelte"
   import IndicatorSet from "./IndicatorSet.svelte"
-  import { builderStore, dndIsDragging } from "stores"
+  import { builderStore, dndIsDragging, hoverStore } from "stores"
 
-  $: componentId = $builderStore.hoverComponentId
+  $: componentId = $hoverStore.hoveredComponentId
   $: zIndex = componentId === $builderStore.selectedComponentId ? 900 : 920
 
   const onMouseOver = e => {
@@ -23,12 +23,12 @@
     }
 
     if (newId !== componentId) {
-      builderStore.actions.hoverComponent(newId)
+      hoverStore.actions.hoverComponent(newId)
     }
   }
 
   const onMouseLeave = () => {
-    builderStore.actions.hoverComponent(null)
+    hoverStore.actions.hoverComponent(null)
   }
 
   onMount(() => {
diff --git a/packages/client/src/index.js b/packages/client/src/index.js
index 044c900c9d..48cbfcb20d 100644
--- a/packages/client/src/index.js
+++ b/packages/client/src/index.js
@@ -7,6 +7,7 @@ import {
   environmentStore,
   dndStore,
   eventStore,
+  hoverStore,
 } from "./stores"
 import loadSpectrumIcons from "@budibase/bbui/spectrum-icons-rollup.js"
 import { get } from "svelte/store"
@@ -32,7 +33,6 @@ const loadBudibase = async () => {
     layout: window["##BUDIBASE_PREVIEW_LAYOUT##"],
     screen: window["##BUDIBASE_PREVIEW_SCREEN##"],
     selectedComponentId: window["##BUDIBASE_SELECTED_COMPONENT_ID##"],
-    hoverComponentId: window["##BUDIBASE_HOVER_COMPONENT_ID##"],
     previewId: window["##BUDIBASE_PREVIEW_ID##"],
     theme: window["##BUDIBASE_PREVIEW_THEME##"],
     customTheme: window["##BUDIBASE_PREVIEW_CUSTOM_THEME##"],
@@ -76,6 +76,8 @@ const loadBudibase = async () => {
       } else {
         dndStore.actions.reset()
       }
+    } else if (type === "hover-component") {
+      hoverStore.actions.hoverComponent(data)
     }
   }
 
diff --git a/packages/client/src/stores/builder.js b/packages/client/src/stores/builder.js
index f92e6b9df9..036558e8b2 100644
--- a/packages/client/src/stores/builder.js
+++ b/packages/client/src/stores/builder.js
@@ -8,7 +8,6 @@ const createBuilderStore = () => {
     inBuilder: false,
     screen: null,
     selectedComponentId: null,
-    hoverComponentId: null,
     editMode: false,
     previewId: null,
     theme: null,
@@ -24,16 +23,6 @@ const createBuilderStore = () => {
   }
   const store = writable(initialState)
   const actions = {
-    hoverComponent: id => {
-      if (id === get(store).hoverComponentId) {
-        return
-      }
-      store.update(state => ({
-        ...state,
-        hoverComponentId: id,
-      }))
-      eventStore.actions.dispatchEvent("hover-component", { id })
-    },
     selectComponent: id => {
       if (id === get(store).selectedComponentId) {
         return
diff --git a/packages/client/src/stores/hover.js b/packages/client/src/stores/hover.js
new file mode 100644
index 0000000000..24f315a126
--- /dev/null
+++ b/packages/client/src/stores/hover.js
@@ -0,0 +1,25 @@
+import { get, writable } from "svelte/store"
+import { eventStore } from "./events.js"
+
+const createHoverStore = () => {
+  const store = writable({
+    hoveredComponentId: null,
+  })
+
+  const hoverComponent = id => {
+    if (id === get(store).hoveredComponentId) {
+      return
+    }
+    store.set({ hoveredComponentId: id })
+    eventStore.actions.dispatchEvent("hover-component", { id })
+  }
+
+  return {
+    ...store,
+    actions: {
+      hoverComponent,
+    },
+  }
+}
+
+export const hoverStore = createHoverStore()
diff --git a/packages/client/src/stores/index.js b/packages/client/src/stores/index.js
index 1b1b9d46bc..2149c72481 100644
--- a/packages/client/src/stores/index.js
+++ b/packages/client/src/stores/index.js
@@ -1,3 +1,5 @@
+import { writable } from "svelte/store"
+
 export { authStore } from "./auth"
 export { appStore } from "./app"
 export { notificationStore } from "./notification"
@@ -27,6 +29,7 @@ export {
   dndIsDragging,
 } from "./dnd"
 export { sidePanelStore } from "./sidePanel"
+export { hoverStore } from "./hover"
 
 // Context stores are layered and duplicated, so it is not a singleton
 export { createContextStore } from "./context"
diff --git a/packages/server/src/api/controllers/static/templates/preview.hbs b/packages/server/src/api/controllers/static/templates/preview.hbs
index e5b97afd66..63c61baa9f 100644
--- a/packages/server/src/api/controllers/static/templates/preview.hbs
+++ b/packages/server/src/api/controllers/static/templates/preview.hbs
@@ -63,7 +63,6 @@
       // Extract data from message
       const {
         selectedComponentId,
-        hoverComponentId,
         layout,
         screen,
         appId,
@@ -82,7 +81,6 @@
       window["##BUDIBASE_PREVIEW_LAYOUT##"] = layout
       window["##BUDIBASE_PREVIEW_SCREEN##"] = screen
       window["##BUDIBASE_SELECTED_COMPONENT_ID##"] = selectedComponentId
-      window["##BUDIBASE_HOVER_COMPONENT_ID##"] = hoverComponentId
       window["##BUDIBASE_PREVIEW_ID##"] = Math.random()
       window["##BUDIBASE_PREVIEW_THEME##"] = theme
       window["##BUDIBASE_PREVIEW_CUSTOM_THEME##"] = customTheme