fix(core): ssr events

.changeset/clear-pugs-make.md

@@ -0,0 +1,5 @@
+---
+"@patternfly/pfe-core": patch
+"@patternfly/elements": patch
+---
+Enable context protocol in SSR scenarios.

.nvmrc

@@ -1 +1 @@
-v20.10.0
+v22.13.0

core/pfe-core/controllers/light-dom-controller.ts

@@ -1,4 +1,4 @@
-import type { ReactiveController, ReactiveElement } from 'lit';
+import { isServer, type ReactiveController, type ReactiveElement } from 'lit';
 
 import { Logger } from './logger.js';
 
@@ -52,9 +52,13 @@ export class LightDOMController implements ReactiveController {
    * Returns a boolean statement of whether or not this component contains any light DOM.
    */
   hasLightDOM(): boolean {
-    return !!(
-      this.host.children.length > 0
-      || (this.host.textContent ?? '').trim().length > 0
-    );
+    if (isServer) {
+      return false;
+    } else {
+      return !!(
+        this.host.children.length > 0
+        || (this.host.textContent ?? '').trim().length > 0
+      );
+    }
   }
 }

core/pfe-core/controllers/scroll-spy-controller.ts

@@ -44,7 +44,7 @@ export class ScrollSpyController implements ReactiveController {
   #rootMargin?: string;
   #threshold: number | number[];
 
-  #getRootNode: () => Node;
+  #getRootNode: () => Node | null;
   #getHash: (el: Element) => string | null;
 
   get #linkChildren(): Element[] {
@@ -92,7 +92,7 @@ export class ScrollSpyController implements ReactiveController {
     this.#rootMargin = options.rootMargin;
     this.#activeAttribute = options.activeAttribute ?? 'active';
     this.#threshold = options.threshold ?? 0.85;
-    this.#getRootNode = () => options.rootNode ?? host.getRootNode();
+    this.#getRootNode = () => options.rootNode ?? host.getRootNode?.() ?? null;
     this.#getHash = options?.getHash ?? ((el: Element) => el.getAttribute('href'));
   }
 

core/pfe-core/controllers/slot-controller.ts

@@ -1,7 +1,5 @@
 import { isServer, type ReactiveController, type ReactiveElement } from 'lit';
 
-import { Logger } from './logger.js';
-
 interface AnonymousSlot {
   hasContent: boolean;
   elements: Element[];
@@ -32,7 +30,9 @@ export interface SlotsConfig {
   deprecations?: Record<string, string>;
 }
 
-function isObjectConfigSpread(
+export type SlotControllerArgs = [SlotsConfig] | (string | null)[];
+
+function isObjectSpread(
   config: ([SlotsConfig] | (string | null)[]),
 ): config is [SlotsConfig] {
   return config.length === 1 && typeof config[0] === 'object' && config[0] !== null;
@@ -55,60 +55,108 @@ export class SlotController implements ReactiveController {
   /** @deprecated use `default` */
   public static anonymous: symbol = this.default;
 
-  #nodes = new Map<string | typeof SlotController.default, Slot>();
+  private static singletons = new WeakMap<ReactiveElement, SlotController>();
 
-  #logger: Logger;
+  #nodes = new Map<string | typeof SlotController.default, Slot>();
 
-  #firstUpdated = false;
+  #slotMapInitialized = false;
 
-  #mo = new MutationObserver(records => this.#onMutation(records));
+  #slotNames: (string | null)[] = [];
 
-  #slotNames: (string | null)[];
+  #ssrHintHasSlotted: (string | null)[] = [];
 
   #deprecations: Record<string, string> = {};
 
-  constructor(public host: ReactiveElement, ...config: ([SlotsConfig] | (string | null)[])) {
-    this.#logger = new Logger(this.host);
+  #mo = new MutationObserver(this.#initSlotMap.bind(this));
 
-    if (isObjectConfigSpread(config)) {
+  constructor(public host: ReactiveElement, ...args: SlotControllerArgs) {
+    const singleton = SlotController.singletons.get(host);
+    if (singleton) {
+      singleton.#initialize(...args);
+      return singleton;
+    }
+    this.#initialize(...args);
+    host.addController(this);
+    SlotController.singletons.set(host, this);
+    if (!this.#slotNames.length) {
+      this.#slotNames = [null];
+    }
+  }
+
+  #initialize(...config: SlotControllerArgs) {
+    if (isObjectSpread(config)) {
       const [{ slots, deprecations }] = config;
       this.#slotNames = slots;
       this.#deprecations = deprecations ?? {};
     } else if (config.length >= 1) {
       this.#slotNames = config;
       this.#deprecations = {};
-    } else {
-      this.#slotNames = [null];
     }
-
-
-    host.addController(this);
   }
 
   async hostConnected(): Promise<void> {
-    this.host.addEventListener('slotchange', this.#onSlotChange as EventListener);
-    this.#firstUpdated = false;
     this.#mo.observe(this.host, { childList: true });
+    this.#ssrHintHasSlotted =
+      this.host
+      // @ts-expect-error: this is a ponyfill for ::has-slotted, is not intended as a public API
+          .ssrHintHasSlotted
+          ?? [];
     // Map the defined slots into an object that is easier to query
     this.#nodes.clear();
-    // Loop over the properties provided by the schema
-    this.#slotNames.forEach(this.#initSlot);
-    Object.values(this.#deprecations).forEach(this.#initSlot);
-    this.host.requestUpdate();
+    this.#initSlotMap();
     // insurance for framework integrations
     await this.host.updateComplete;
     this.host.requestUpdate();
   }
 
+  hostDisconnected(): void {
+    this.#mo.disconnect();
+  }
+
   hostUpdated(): void {
-    if (!this.#firstUpdated) {
-      this.#slotNames.forEach(this.#initSlot);
-      this.#firstUpdated = true;
+    if (!this.#slotMapInitialized) {
+      this.#initSlotMap();
     }
   }
 
-  hostDisconnected(): void {
-    this.#mo.disconnect();
+  #initSlotMap() {
+    // Loop over the properties provided by the schema
+    for (const slotName of this.#slotNames
+        .concat(Object.values(this.#deprecations))) {
+      const slotId = slotName || SlotController.default;
+      const name = slotName ?? '';
+      const elements = this.#getChildrenForSlot(slotId);
+      const slot = this.#getSlotElement(slotId);
+      const hasContent =
+          isServer ? this.#ssrHintHasSlotted.includes(slotName)
+        : !!elements.length || !!slot?.assignedNodes?.()?.filter(x => x.textContent?.trim()).length;
+      this.#nodes.set(slotId, { elements, name, hasContent, slot });
+    }
+    this.host.requestUpdate();
+    this.#slotMapInitialized = true;
+  }
+
+  #getSlotElement(slotId: string | symbol) {
+    if (isServer) {
+      return null;
+    } else {
+      const selector =
+      slotId === SlotController.default ? 'slot:not([name])' : `slot[name="${slotId as string}"]`;
+      return this.host.shadowRoot?.querySelector?.<HTMLSlotElement>(selector) ?? null;
+    }
+  }
+
+  #getChildrenForSlot<T extends Element = Element>(
+    name: string | typeof SlotController.default,
+  ): T[] {
+    if (isServer) {
+      return [];
+    } else if (this.#nodes.has(name)) {
+      return this.#nodes.get(name)!.slot?.assignedElements?.() as T[];
+    } else {
+      const children = Array.from(this.host.children) as T[];
+      return children.filter(isSlot(name));
+    }
   }
 
   /**
@@ -143,19 +191,11 @@ export class SlotController implements ReactiveController {
    * @example this.hasSlotted('header');
    */
   hasSlotted(...names: (string | null | undefined)[]): boolean {
-    if (isServer) {
-      return this.host
-          .getAttribute('ssr-hint-has-slotted')
-          ?.split(',')
-          .map(name => name.trim())
-          .some(name => names.includes(name === 'default' ? null : name)) ?? false;
-    } else {
-      const slotNames = Array.from(names, x => x == null ? SlotController.default : x);
-      if (!slotNames.length) {
-        slotNames.push(SlotController.default);
-      }
-      return slotNames.some(x => this.#nodes.get(x)?.hasContent ?? false);
+    const slotNames = Array.from(names, x => x == null ? SlotController.default : x);
+    if (!slotNames.length) {
+      slotNames.push(SlotController.default);
     }
+    return slotNames.some(x => this.#nodes.get(x)?.hasContent ?? false);
   }
 
   /**
@@ -168,42 +208,4 @@ export class SlotController implements ReactiveController {
   isEmpty(...names: (string | null | undefined)[]): boolean {
     return !this.hasSlotted(...names);
   }
-
-  #onSlotChange = (event: Event & { target: HTMLSlotElement }) => {
-    const slotName = event.target.name;
-    this.#initSlot(slotName);
-    this.host.requestUpdate();
-  };
-
-  #onMutation = async (records: MutationRecord[]) => {
-    const changed = [];
-    for (const { addedNodes, removedNodes } of records) {
-      for (const node of [...addedNodes, ...removedNodes]) {
-        if (node instanceof HTMLElement && node.slot) {
-          this.#initSlot(node.slot);
-          changed.push(node.slot);
-        }
-      }
-    }
-    this.host.requestUpdate();
-  };
-
-  #getChildrenForSlot<T extends Element = Element>(
-    name: string | typeof SlotController.default,
-  ): T[] {
-    const children = Array.from(this.host.children) as T[];
-    return children.filter(isSlot(name));
-  }
-
-  #initSlot = (slotName: string | null) => {
-    const name = slotName || SlotController.default;
-    const elements = this.#nodes.get(name)?.slot?.assignedElements?.()
-      ?? this.#getChildrenForSlot(name);
-    const selector = slotName ? `slot[name="${slotName}"]` : 'slot:not([name])';
-    const slot = this.host.shadowRoot?.querySelector?.<HTMLSlotElement>(selector) ?? null;
-    const nodes = slot?.assignedNodes?.();
-    const hasContent = !!elements.length || !!nodes?.filter(x => x.textContent?.trim()).length;
-    this.#nodes.set(name, { elements, name: slotName ?? '', hasContent, slot });
-    this.#logger.debug(slotName, hasContent);
-  };
 }

core/pfe-core/decorators/slots.ts

@@ -0,0 +1,27 @@
+import type { ReactiveElement } from 'lit';
+
+import { SlotController, type SlotControllerArgs } from '../controllers/slot-controller.js';
+
+/**
+ * Enable ssr hints for element
+ * @param args a spread of slot names, or a config object.
+ * @see SlotController constructor args
+ */
+export function slots<T extends typeof ReactiveElement>(...args: SlotControllerArgs) {
+  return function(klass: T): void {
+    klass.createProperty('ssrHintHasSlotted', {
+      attribute: 'ssr-hint-has-slotted',
+      converter: {
+        fromAttribute(slots) {
+          return (slots ?? '')
+              .split(/[, ]/)
+              .map(x => x.trim())
+              .map(x => x === 'default' ? null : x);
+        },
+      },
+    });
+    klass.addInitializer(instance => {
+      new SlotController(instance, ...args);
+    });
+  };
+}

core/pfe-core/functions/context.ts

@@ -7,6 +7,11 @@ function makeContextRoot() {
   const root = new ContextRoot();
   if (!isServer) {
     root.attach(document.body);
+  } else {
+    root.attach(
+      // @ts-expect-error: enable context root in ssr
+      globalThis.litServerRoot,
+    );
   }
   return root;
 }

core/pfe-core/package.json

@@ -62,8 +62,8 @@
   },
   "dependencies": {
     "@floating-ui/dom": "^1.6.10",
-    "@lit/context": "^1.1.2",
-    "lit": "^3.2.0"
+    "@lit/context": "^1.1.3",
+    "lit": "^3.2.1"
   },
   "repository": {
     "type": "git",

core/pfe-core/ssr-shims.ts

@@ -1,3 +1,5 @@
+import { installWindowOnGlobal } from '@lit-labs/ssr/lib/dom-shim.js';
+
 class ObserverShim {
   observe(): void {
     void 0;
@@ -17,33 +19,7 @@ class MiniHTMLTemplateElement extends MiniHTMLElement {
   content = { cloneNode: (): string => this.innerHTML };
 }
 
-class MiniDocument {
-  createElement(tagName: string): MiniHTMLElement {
-    switch (tagName) {
-      case 'template':
-        return new MiniHTMLTemplateElement(tagName);
-      default:
-        return new MiniHTMLElement(tagName);
-    }
-  }
-}
-
-// @ts-expect-error: this runs in node
-globalThis.window ??= globalThis;
-// @ts-expect-error: this runs in node
-globalThis.document ??= new MiniDocument();
-// @ts-expect-error: this runs in node
-globalThis.navigator ??= { userAgent: '' };
-// @ts-expect-error: this runs in node
-globalThis.ErrorEvent ??= Event;
-// @ts-expect-error: this runs in node
-globalThis.IntersectionObserver ??= ObserverShim;
-// @ts-expect-error: this runs in node
-globalThis.MutationObserver ??= ObserverShim;
-// @ts-expect-error: this runs in node
-globalThis.ResizeObserver ??= ObserverShim;
-// @ts-expect-error: this runs in node
-globalThis.getComputedStyle ??= function() {
+function getComputedStyle() {
   return {
     getPropertyPriority() {
       return '';
@@ -52,7 +28,27 @@ globalThis.getComputedStyle ??= function() {
       return '';
     },
   };
-}
+};
 
-;
+// @ts-expect-error: opt in to event support in ssr
+globalThis.litSsrCallConnectedCallback = true;
 
+installWindowOnGlobal({
+  ErrorEvent: Event,
+  IntersectionObserver: ObserverShim,
+  MutationObserver: ObserverShim,
+  ResizeObserver: ObserverShim,
+  getComputedStyle,
+});
+
+// @ts-expect-error: this runs in node
+globalThis.navigator.userAgent ??= '@lit-labs/ssr';
+
+globalThis.document.createElement = function createElement(tagName: string): HTMLElement {
+  switch (tagName) {
+    case 'template':
+      return new MiniHTMLTemplateElement(tagName) as unknown as HTMLElement;
+    default:
+      return new MiniHTMLElement(tagName) as HTMLElement;
+  }
+};