Add proper hot reloading of app preview when styles change

packages/client/src/components/Component.svelte

@@ -1,5 +1,6 @@
 <script>
   import { getContext, setContext } from "svelte"
+  import { writable } from "svelte/store"
   import * as ComponentLibrary from "@budibase/standard-components"
   import Router from "./Router.svelte"
 
@@ -28,21 +29,23 @@
   }
 
   // Extract component definition info
-  const componentName = extractComponentName(definition._component)
-  const constructor = getComponentConstructor(componentName)
-  const componentProps = extractValidProps(definition)
-  const dataContext = getContext("data")
-  const enrichedProps = dataContext.actions.enrichDataBindings(componentProps)
-  const children = definition._children
+  $: componentName = extractComponentName(definition._component)
+  $: constructor = getComponentConstructor(componentName)
+  $: componentProps = extractValidProps(definition)
+  $: dataContext = getContext("data")
+  $: enrichedProps = dataContext.actions.enrichDataBindings(componentProps)
+  $: children = definition._children
 
-  // Set contexts to be consumed by component
-  setContext("style", { ...definition._styles, id: definition._id })
+  // Set observable style context
+  const styleStore = writable({})
+  setContext("style", styleStore)
+  $: styleStore.set({ ...definition._styles, id: definition._id })
 </script>
 
 {#if constructor}
   <svelte:component this={constructor} {...enrichedProps}>
     {#if children && children.length}
-      {#each children as child}
+      {#each children as child (child._id)}
         <svelte:self definition={child} />
       {/each}
     {/if}

packages/client/src/components/DataProvider.svelte

@@ -1,25 +1,19 @@
 <script>
-  import { onMount, getContext, setContext } from "svelte"
+  import { getContext, setContext } from "svelte"
   import { createDataContextStore } from "../store"
 
   export let row
 
   // Get current contexts
   const dataContext = getContext("data")
-  const { id } = getContext("style")
+  const styles = getContext("style")
 
   // Clone current context to this context
   const newDataContext = createDataContextStore($dataContext)
   setContext("data", newDataContext)
 
   // Add additional layer to context
-  let loaded = false
-  onMount(() => {
-    newDataContext.actions.addContext(row, id)
-    loaded = true
-  })
+  $: newDataContext.actions.addContext(row, $styles.id)
 </script>
 
-{#if loaded}
-  <slot />
-{/if}
+<slot />

packages/client/src/components/Router.svelte

@@ -1,7 +1,7 @@
 <script>
   import { getContext } from "svelte"
   import Router from "svelte-spa-router"
-  import { routeStore, screenStore } from "../store"
+  import { routeStore } from "../store"
   import Screen from "./Screen.svelte"
 
   const { styleable } = getContext("sdk")
@@ -26,7 +26,7 @@
 </script>
 
 {#if routerConfig}
-  <div use:styleable={styles}>
+  <div use:styleable={$styles}>
     <Router on:routeLoading={onRouteLoading} routes={routerConfig} />
   </div>
 {/if}

packages/client/src/components/Screen.svelte

@@ -11,8 +11,11 @@
 
   // Redirect to home page if no matching route
   $: screenDefinition == null && routeStore.actions.navigate("/")
+
+  // Make a screen array so we can use keying to properly re-render each screen
+  $: screens = screenDefinition ? [screenDefinition] : []
 </script>
 
-{#if screenDefinition}
-  <Component definition={screenDefinition} />
-{/if}
+{#each screens as screen (screen._id)}
+  <Component definition={screen} />
+{/each}

packages/client/src/index.js

@@ -1,16 +1,22 @@
 import ClientApp from "./components/ClientApp.svelte"
+import { builderStore } from "./store"
 
 let app
 
 const loadBudibase = () => {
-  // Destroy old app if one exists
-  if (app) {
-    app.$destroy()
-  }
-  // Create new app
-  app = new ClientApp({
-    target: window.document.body,
+  // Update builder store with any builder flags
+  builderStore.set({
+    inBuilder: !!window["##BUDIBASE_IN_BUILDER##"],
+    page: window["##BUDIBASE_PREVIEW_PAGE##"],
+    screen: window["##BUDIBASE_PREVIEW_SCREEN##"],
   })
+
+  // Create app if one hasn't been created yet
+  if (!app) {
+    app = new ClientApp({
+      target: window.document.body,
+    })
+  }
 }
 
 // Attach to window so the HTML template can call this when it loads

packages/client/src/store/builder.js

@@ -0,0 +1,12 @@
+import { writable } from "svelte/store"
+
+const createBuilderStore = () => {
+  const initialState = {
+    inBuilder: false,
+    page: null,
+    screen: null,
+  }
+  return writable(initialState)
+}
+
+export const builderStore = createBuilderStore()

packages/client/src/store/index.js

@@ -2,3 +2,4 @@ export { authStore } from "./auth"
 export { routeStore } from "./routes"
 export { screenStore } from "./screens"
 export { createDataContextStore } from "./dataContext"
+export { builderStore } from "./builder"

packages/client/src/store/screens.js

@@ -1,5 +1,6 @@
 import { writable, derived } from "svelte/store"
 import { routeStore } from "./routes"
+import { builderStore } from "./builder"
 import * as API from "../api"
 import { getAppId } from "../utils"
 
@@ -8,36 +9,37 @@ const createScreenStore = () => {
     screens: [],
     page: {},
   })
-  const store = derived([config, routeStore], ([$config, $routeStore]) => {
-    const { screens, page } = $config
-    const activeScreen =
-      screens.length === 1
-        ? screens[0]
-        : screens.find(
+  const store = derived(
+    [config, routeStore, builderStore],
+    ([$config, $routeStore, $builderStore]) => {
+      let page
+      let activeScreen
+      if ($builderStore.inBuilder) {
+        // Use builder defined definitions if inside the builder preview
+        page = $builderStore.page
+        activeScreen = $builderStore.screen
+      } else {
+        // Otherwise find the correct screen by matching the current route
+        page = $config.page
+        const { screens } = $config
+        if (screens.length === 1) {
+          activeScreen = screens[0]
+        } else {
+          activeScreen = screens.find(
             screen => screen.routing.route === $routeStore.activeRoute
           )
-    return {
-      screens,
-      page,
-      activeScreen,
+        }
+      }
+      return { page, activeScreen }
     }
-  })
+  )
 
   const fetchScreens = async () => {
-    let screens
-    let page
-    const inBuilder = !!window["##BUDIBASE_IN_BUILDER##"]
-    if (inBuilder) {
-      // Load screen and page from the window object if in the builder
-      screens = [window["##BUDIBASE_PREVIEW_SCREEN##"]]
-      page = window["##BUDIBASE_PREVIEW_PAGE##"]
-    } else {
-      // Otherwise load from API
-      const appDefinition = await API.fetchAppDefinition(getAppId())
-      screens = appDefinition.screens
-      page = appDefinition.page
-    }
-    config.set({ screens, page })
+    const appDefinition = await API.fetchAppDefinition(getAppId())
+    config.set({
+      screens: appDefinition.screens,
+      page: appDefinition.page,
+    })
   }
 
   return {

packages/client/src/utils/styleable.js

@@ -1,7 +1,13 @@
+import { getContext } from "svelte"
+import { get } from "svelte/store"
+
+/**
+ * Helper to build a CSS string from a style object
+ */
 const buildStyleString = styles => {
   let str = ""
   Object.entries(styles).forEach(([style, value]) => {
-    if (style && value) {
+    if (style && value != null) {
       str += `${style}: ${value}; `
     }
   })
@@ -12,35 +18,52 @@ const buildStyleString = styles => {
  * Svelte action to apply correct component styles.
  */
 export const styleable = (node, styles = {}) => {
-  const normalStyles = styles.normal || {}
-  const hoverStyles = {
-    ...normalStyles,
-    ...styles.hover,
+  let applyNormalStyles
+  let applyHoverStyles
+
+  // Creates event listeners and applies initial styles
+  const setupStyles = newStyles => {
+    const normalStyles = newStyles.normal || {}
+    const hoverStyles = {
+      ...normalStyles,
+      ...newStyles.hover,
+    }
+
+    applyNormalStyles = () => {
+      node.style = buildStyleString(normalStyles)
+    }
+
+    applyHoverStyles = () => {
+      node.style = buildStyleString(hoverStyles)
+    }
+
+    // Add listeners to toggle hover styles
+    node.addEventListener("mouseover", applyHoverStyles)
+    node.addEventListener("mouseout", applyNormalStyles)
+    node.setAttribute("data-bb-id", newStyles.id)
+
+    // Apply initial normal styles
+    applyNormalStyles()
   }
 
-  function applyNormalStyles() {
-    node.style = buildStyleString(normalStyles)
+  // Removes the current event listeners
+  const removeListeners = () => {
+    node.removeEventListener("mouseover", applyHoverStyles)
+    node.removeEventListener("mouseout", applyNormalStyles)
   }
 
-  function applyHoverStyles() {
-    node.style = buildStyleString(hoverStyles)
-  }
-
-  // Add listeners to toggle hover styles
-  node.addEventListener("mouseover", applyHoverStyles)
-  node.addEventListener("mouseout", applyNormalStyles)
-
-  // Apply normal styles initially
-  applyNormalStyles()
-
-  // Also apply data tags so we know how to reference each component
-  node.setAttribute("data-bb-id", styles.id)
+  // Apply initial styles
+  setupStyles(styles)
 
   return {
-    // Clean up event listeners when component is destroyed
+    // Clean up old listeners and apply new ones on update
+    update: newStyles => {
+      removeListeners()
+      setupStyles(newStyles)
+    },
+    // Clean up listeners when component is destroyed
     destroy: () => {
-      node.removeEventListener("mouseover", applyHoverStyles)
-      node.removeEventListener("mouseout", applyNormalStyles)
+      removeListeners()
     },
   }
 }

packages/standard-components/src/Button.svelte

@@ -9,7 +9,7 @@
   export let text
 </script>
 
-<button class="default" disabled={disabled || false} use:styleable={styles}>
+<button class="default" disabled={disabled || false} use:styleable={$styles}>
   {text}
 </button>
 

packages/standard-components/src/Card.svelte

@@ -26,7 +26,7 @@
   $: showImage = !!imageUrl
 </script>
 
-<div use:cssVars={cssVariables} class="container" use:styleable={styles}>
+<div use:cssVars={cssVariables} class="container" use:styleable={$styles}>
   {#if showImage}<img class="image" src={imageUrl} alt="" />{/if}
   <div class="content">
     <h2 class="heading">{heading}</h2>

packages/standard-components/src/CardHorizontal.svelte

@@ -29,7 +29,7 @@
   $: showImage = !!imageUrl
 </script>
 
-<div use:cssVars={cssVariables} class="container" use:styleable={styles}>
+<div use:cssVars={cssVariables} class="container" use:styleable={$styles}>
   {#if showImage}<img class="image" src={imageUrl} alt="" />{/if}
   <div class="content">
     <main>

packages/standard-components/src/Container.svelte

@@ -9,55 +9,55 @@
 </script>
 
 {#if type === 'div'}
-  <div use:styleable={styles}>
+  <div use:styleable={$styles}>
     <slot />
   </div>
 {:else if type === 'header'}
-  <header use:styleable={styles}>
+  <header use:styleable={$styles}>
     <slot />
   </header>
 {:else if type === 'main'}
-  <main use:styleable={styles}>
+  <main use:styleable={$styles}>
     <slot />
   </main>
 {:else if type === 'footer'}
-  <footer use:styleable={styles}>
+  <footer use:styleable={$styles}>
     <slot />
   </footer>
 {:else if type === 'aside'}
-  <aside use:styleable={styles}>
+  <aside use:styleable={$styles}>
     <slot />
   </aside>
 {:else if type === 'summary'}
-  <summary use:styleable={styles}>
+  <summary use:styleable={$styles}>
     <slot />
   </summary>
 {:else if type === 'details'}
-  <details use:styleable={styles}>
+  <details use:styleable={$styles}>
     <slot />
   </details>
 {:else if type === 'article'}
-  <article use:styleable={styles}>
+  <article use:styleable={$styles}>
     <slot />
   </article>
 {:else if type === 'nav'}
-  <nav use:styleable={styles}>
+  <nav use:styleable={$styles}>
     <slot />
   </nav>
 {:else if type === 'mark'}
-  <mark use:styleable={styles}>
+  <mark use:styleable={$styles}>
     <slot />
   </mark>
 {:else if type === 'figure'}
-  <figure use:styleable={styles}>
+  <figure use:styleable={$styles}>
     <slot />
   </figure>
 {:else if type === 'figcaption'}
-  <figcaption use:styleable={styles}>
+  <figcaption use:styleable={$styles}>
     <slot />
   </figcaption>
 {:else if type === 'paragraph'}
-  <p use:styleable={styles}>
+  <p use:styleable={$styles}>
     <slot />
   </p>
 {/if}

packages/standard-components/src/DatePicker.svelte

@@ -14,6 +14,6 @@
   }
 </script>
 
-<div use:styleable={styles}>
+<div use:styleable={$styles}>
   <DatePicker {placeholder} on:change={handleChange} {value} />
 </div>

packages/standard-components/src/Embed.svelte

@@ -7,7 +7,7 @@
   export let embed
 </script>
 
-<div use:styleable={styles}>
+<div use:styleable={$styles}>
   {@html embed}
 </div>
 

packages/standard-components/src/Form.svelte

@@ -27,7 +27,7 @@
   }
 </script>
 
-<div class="form-content" use:styleable={styles}>
+<div class="form-content" use:styleable={$styles}>
   <!--  <ErrorsBox errors={$store.saveRowErrors || {}} />-->
   {#each fields as field}
     <div class="form-field" class:wide>

packages/standard-components/src/Heading.svelte

@@ -10,15 +10,15 @@
 </script>
 
 {#if type === 'h1'}
-  <h1 class={className} use:styleable={styles}>{text}</h1>
+  <h1 class={className} use:styleable={$styles}>{text}</h1>
 {:else if type === 'h2'}
-  <h2 class={className} use:styleable={styles}>{text}</h2>
+  <h2 class={className} use:styleable={$styles}>{text}</h2>
 {:else if type === 'h3'}
-  <h3 class={className} use:styleable={styles}>{text}</h3>
+  <h3 class={className} use:styleable={$styles}>{text}</h3>
 {:else if type === 'h4'}
-  <h4 class={className} use:styleable={styles}>{text}</h4>
+  <h4 class={className} use:styleable={$styles}>{text}</h4>
 {:else if type === 'h5'}
-  <h5 class={className} use:styleable={styles}>{text}</h5>
+  <h5 class={className} use:styleable={$styles}>{text}</h5>
 {:else if type === 'h6'}
-  <h6 class={className} use:styleable={styles}>{text}</h6>
+  <h6 class={className} use:styleable={$styles}>{text}</h6>
 {/if}

packages/standard-components/src/Icon.svelte

@@ -13,4 +13,4 @@
 <i
   style={`color: ${color};`}
   class={`${icon} ${size}`}
-  use:styleable={styles} />
+  use:styleable={$styles} />

packages/standard-components/src/Image.svelte

@@ -17,4 +17,4 @@
   class={className}
   src={url}
   alt={description}
-  use:styleable={styles} />
+  use:styleable={$styles} />

packages/standard-components/src/Input.svelte

@@ -18,4 +18,4 @@
   {type}
   {value}
   on:change={onchange}
-  use:styleable={styles} />
+  use:styleable={$styles} />

packages/standard-components/src/Link.svelte

@@ -11,7 +11,7 @@
   $: target = openInNewTab ? "_blank" : "_self"
 </script>
 
-<a href={url} use:linkable {target} use:styleable={styles}>
+<a href={url} use:linkable {target} use:styleable={$styles}>
   {text}
   <slot />
 </a>

packages/standard-components/src/List.svelte

@@ -17,7 +17,7 @@
   })
 </script>
 
-<div use:styleable={styles}>
+<div use:styleable={$styles}>
   {#each rows as row}
     <DataProvider {row}>
       <slot />

packages/standard-components/src/Login.svelte

@@ -29,7 +29,7 @@
   }
 </script>
 
-<div class="root" use:styleable={styles}>
+<div class="root" use:styleable={$styles}>
   <div class="content">
     {#if logo}
       <div class="logo-container"><img src={logo} alt="logo" /></div>

packages/standard-components/src/Navigation.svelte

@@ -12,7 +12,7 @@
   }
 </script>
 
-<div class="nav" use:styleable={styles}>
+<div class="nav" use:styleable={$styles}>
   <div class="nav__top">
     <a href="/" use:linkable>
       {#if logoUrl}

packages/standard-components/src/RichText.svelte

@@ -23,6 +23,6 @@
   }
 </script>
 
-<div use:styleable={styles}>
+<div use:styleable={$styles}>
   <RichText bind:content={value} {options} />
 </div>

packages/standard-components/src/ScreenSlotPlaceholder.svelte

@@ -5,7 +5,7 @@
   const { styleable } = getContext("sdk")
 </script>
 
-<div use:styleable={styles}>
+<div use:styleable={$styles}>
   <h1>Screen Slot</h1>
   <span>
     The screens that you create will be displayed inside this box.

packages/standard-components/src/StackedList.svelte

@@ -14,7 +14,7 @@
   $: showImage = !!imageUrl
 </script>
 
-<div class="container" use:styleable={styles}>
+<div class="container" use:styleable={$styles}>
   <a href={destinationUrl}>
     <div class="content">
       {#if showImage}

packages/standard-components/src/Text.svelte

@@ -12,28 +12,28 @@
 </script>
 
 {#if isTag('none')}
-  <span use:styleable={styles}>{text}</span>
+  <span use:styleable={$styles}>{text}</span>
 {:else if isTag('bold')}
-  <b class={className} use:styleable={styles}>{text}</b>
+  <b class={className} use:styleable={$styles}>{text}</b>
 {:else if isTag('strong')}
-  <strong class={className} use:styleable={styles}>{text}</strong>
+  <strong class={className} use:styleable={$styles}>{text}</strong>
 {:else if isTag('italic')}
-  <i class={className} use:styleable={styles}>{text}</i>
+  <i class={className} use:styleable={$styles}>{text}</i>
 {:else if isTag('emphasis')}
-  <em class={className} use:styleable={styles}>{text}</em>
+  <em class={className} use:styleable={$styles}>{text}</em>
 {:else if isTag('mark')}
-  <mark class={className} use:styleable={styles}>{text}</mark>
+  <mark class={className} use:styleable={$styles}>{text}</mark>
 {:else if isTag('small')}
-  <small class={className} use:styleable={styles}>{text}</small>
+  <small class={className} use:styleable={$styles}>{text}</small>
 {:else if isTag('del')}
-  <del class={className} use:styleable={styles}>{text}</del>
+  <del class={className} use:styleable={$styles}>{text}</del>
 {:else if isTag('ins')}
-  <ins class={className} use:styleable={styles}>{text}</ins>
+  <ins class={className} use:styleable={$styles}>{text}</ins>
 {:else if isTag('sub')}
-  <sub class={className} use:styleable={styles}>{text}</sub>
+  <sub class={className} use:styleable={$styles}>{text}</sub>
 {:else if isTag('sup')}
-  <sup class={className} use:styleable={styles}>{text}</sup>
-{:else}<span use:styleable={styles}>{text}</span>{/if}
+  <sup class={className} use:styleable={$styles}>{text}</sup>
+{:else}<span use:styleable={$styles}>{text}</span>{/if}
 
 <style>
   span {

packages/standard-components/src/charts/ApexChart.svelte

@@ -9,9 +9,9 @@
 </script>
 
 {#if options}
-  <div use:chart={options} use:styleable={styles} />
+  <div use:chart={options} use:styleable={$styles} />
 {:else if options === false}
-  <div use:styleable={styles}>Invalid chart options</div>
+  <div use:styleable={$styles}>Invalid chart options</div>
 {/if}
 
 <style>

packages/standard-components/src/grid/Component.svelte

@@ -27,7 +27,13 @@
   export let detailUrl
 
   // Add setting height as css var to allow grid to use correct height
-  styles.normal["--grid-height"] = `${height}px`
+  $: gridStyles = {
+    ...$styles,
+    normal: {
+      ...$styles.normal,
+      ["--grid-height"]: `${height}px`,
+    },
+  }
 
   // These can never change at runtime so don't need to be reactive
   let canEdit = editable && datasource && datasource.type !== "view"
@@ -143,7 +149,7 @@
     href="https://cdn.jsdelivr.net/npm/flatpickr/dist/flatpickr.min.css" />
 </svelte:head>
 
-<div class="container" use:styleable={styles}>
+<div class="container" use:styleable={gridStyles}>
   {#if dataLoaded}
     {#if canAddDelete}
       <div class="controls">