Compress faster by running brotli in parallel

2026-08-04 21:52:59 +00:00 · 2026-08-04 15:54:17 +02:00
60 changed files with 555 additions and 429 deletions
@@ -0,0 +1,46 @@
+// Gulp transform that brotli-compresses files, several at a time.
+//
+// Drop-in replacement for gulp-brotli. zlib already does the work off the main
+// thread, but that plugin wraps it in through2, which waits for each file
+// before starting the next, so only one compression is ever in flight. The
+// compressed bytes are unchanged; only how many run at once differs.
+//
+// The real ceiling is libuv's threadpool, which zlib runs on. It sizes itself
+// from UV_THREADPOOL_SIZE before any JavaScript runs, so it can only be raised
+// from the environment, never from inside the build.
+
+import { availableParallelism } from "node:os";
+import { buffer as readStream } from "node:stream/consumers";
+import { promisify } from "node:util";
+import { brotliCompress } from "node:zlib";
+import { ParallelTransform } from "./parallel-transform.mjs";
+
+const EXTENSION = ".br";
+
+const compress = promisify(brotliCompress);
+
+/**
+ * @param {object} [options]
+ * @param {boolean} [options.skipLarger] Drop files that compression grows.
+ * @param {object} [options.params] Brotli parameters, passed to zlib as-is.
+ */
+export default ({ skipLarger = false, params } = {}) =>
+  new ParallelTransform(availableParallelism(), async (file) => {
+    if (file.isNull()) {
+      return file;
+    }
+    if (file.isStream()) {
+      file.contents = await readStream(file.contents);
+    }
+
+    const compressed = await compress(file.contents, { params });
+    if (skipLarger && compressed.length >= file.contents.length) {
+      // Dropped rather than passed through, as gulp-brotli did: the
+      // uncompressed file is already in the output directory.
+      return undefined;
+    }
+
+    file.contents = compressed;
+    file.path += EXTENSION;
+    return file;
+  });
@@ -2,7 +2,7 @@

 import { constants } from "node:zlib";
 import gulp from "gulp";
-import brotli from "gulp-brotli";
+import brotli from "../brotli.mjs";
 import paths from "../paths.cjs";
 import zopfli from "../zopfli.mjs";

@@ -0,0 +1,64 @@
+// Object-mode transform that keeps several files in flight at once.
+//
+// through2 and node's Transform both wait for the previous callback before
+// handling the next file, which serialises asynchronous work down to one file
+// at a time. This keeps `limit` files in flight and applies backpressure beyond
+// that. Files are emitted in completion order rather than input order.
+
+import { Transform } from "node:stream";
+
+export class ParallelTransform extends Transform {
+  #limit;
+
+  #handle;
+
+  #inFlight = 0;
+
+  #resume;
+
+  #finish;
+
+  constructor(limit, handle) {
+    super({ objectMode: true, highWaterMark: limit });
+    this.#limit = limit;
+    this.#handle = handle;
+  }
+
+  // eslint-disable-next-line @typescript-eslint/naming-convention -- node's Transform API
+  _transform(file, _encoding, callback) {
+    this.#inFlight += 1;
+    this.#handle(file)
+      .then((result) => {
+        if (result) {
+          this.push(result);
+        }
+      })
+      .catch((error) => this.destroy(error))
+      .finally(() => {
+        this.#inFlight -= 1;
+        const resume = this.#resume;
+        this.#resume = undefined;
+        resume?.();
+        if (this.#inFlight === 0) {
+          const finish = this.#finish;
+          this.#finish = undefined;
+          finish?.();
+        }
+      });
+
+    if (this.#inFlight < this.#limit) {
+      callback();
+    } else {
+      this.#resume = callback;
+    }
+  }
+
+  // eslint-disable-next-line @typescript-eslint/naming-convention -- node's Transform API
+  _flush(callback) {
+    if (this.#inFlight === 0) {
+      callback();
+    } else {
+      this.#finish = callback;
+    }
+  }
+}
@@ -6,9 +6,9 @@
 // instance per worker parallelises it; the output bytes are unchanged.

 import { availableParallelism } from "node:os";
-import { Transform } from "node:stream";
 import { buffer as readStream } from "node:stream/consumers";
 import { Worker } from "node:worker_threads";
+import { ParallelTransform } from "./parallel-transform.mjs";

 const WORKER_URL = new URL("./zopfli-worker.mjs", import.meta.url);
 const EXTENSION = ".gz";
@@ -112,65 +112,6 @@ const sharedPool = () => {
  return pool;
 };

-// through2 and node's Transform both wait for the previous callback before
-// handling the next file, which would serialise the pool down to one worker.
-// This keeps `limit` files in flight and applies backpressure beyond that.
-class ParallelTransform extends Transform {
-  #limit;
-
-  #handle;
-
-  #inFlight = 0;
-
-  #resume;
-
-  #finish;
-
-  constructor(limit, handle) {
-    super({ objectMode: true, highWaterMark: limit });
-    this.#limit = limit;
-    this.#handle = handle;
-  }
-
-  // eslint-disable-next-line @typescript-eslint/naming-convention -- node's Transform API
-  _transform(file, _encoding, callback) {
-    this.#inFlight += 1;
-    this.#handle(file)
-      .then((result) => {
-        if (result) {
-          this.push(result);
-        }
-      })
-      .catch((error) => this.destroy(error))
-      .finally(() => {
-        this.#inFlight -= 1;
-        const resume = this.#resume;
-        this.#resume = undefined;
-        resume?.();
-        if (this.#inFlight === 0) {
-          const finish = this.#finish;
-          this.#finish = undefined;
-          finish?.();
-        }
-      });
-
-    if (this.#inFlight < this.#limit) {
-      callback();
-    } else {
-      this.#resume = callback;
-    }
-  }
-
-  // eslint-disable-next-line @typescript-eslint/naming-convention -- node's Transform API
-  _flush(callback) {
-    if (this.#inFlight === 0) {
-      callback();
-    } else {
-      this.#finish = callback;
-    }
-  }
-}
-
 /**
 * @param {object} [options]
 * @param {number} [options.threshold] Skip files smaller than this many bytes.
@@ -111,17 +111,7 @@ export default tseslint.config(
      "no-bitwise": "error",
      "no-console": "error",
      "no-restricted-globals": [2, "event"],
-      "no-restricted-syntax": [
-        "error",
-        "LabeledStatement",
-        "WithStatement",
-        {
-          selector:
-            "CallExpression[callee.property.name=/^(push|replace)State$/]",
-          message:
-            "Use navigate(), updateHistoryState() or replaceCurrentUrl() from common/navigate. History entries carry the app's own bookkeeping, which a raw pushState/replaceState drops.",
-        },
-      ],
+      "no-restricted-syntax": ["error", "LabeledStatement", "WithStatement"],
      "wc/no-self-class": "off",

      // import-x rules
@@ -232,24 +222,6 @@ export default tseslint.config(
      ],
    },
  },
-  {
-    // These own history entries themselves: the navigation helpers, the dialog
-    // stack, the boot paths that run before the app has any state to keep, and
-    // the tests that fabricate entries to simulate a document load.
-    files: [
-      "src/common/navigate.ts",
-      "src/dialogs/make-dialog-manager.ts",
-      "src/state/url-sync-mixin.ts",
-      "src/panels/config/automation/add-automation-element-dialog.ts",
-      "src/entrypoints/core.ts",
-      "src/onboarding/**/*.ts",
-      "cast/**/*.ts",
-      "test/**/*.ts",
-    ],
-    rules: {
-      "no-restricted-syntax": ["error", "LabeledStatement", "WithStatement"],
-    },
-  },
  {
    files: ["src/util/recorder-worklet.js"],
    languageOptions: {
@@ -188,7 +188,6 @@
    "glob": "13.0.6",
    "globals": "17.8.0",
    "gulp": "5.0.1",
-    "gulp-brotli": "3.0.0",
    "gulp-json-transform": "0.5.0",
    "gulp-rename": "2.1.0",
    "html-minifier-terser": "7.2.0",
@@ -1,9 +1,8 @@
 import type { ReactiveElement } from "lit";
-import { updateHistoryState } from "../navigate";
 import { throttle } from "../util/throttle";

 const throttleReplaceState = throttle((value) => {
-  updateHistoryState({ scrollPosition: value });
+  history.replaceState({ scrollPosition: value }, "");
 }, 300);

 export function restoreScroll(selector: string) {
@@ -1,7 +1,6 @@
 import { closeAllDialogs } from "../dialogs/make-dialog-manager";
 import { fireEvent } from "./dom/fire_event";
 import { mainWindow } from "./dom/get_main_window";
-import { currentPath } from "./url/current-path";

 declare global {
  // for fire event
@@ -18,26 +17,6 @@ export interface NavigateOptions {
 // max time to wait for dialogs to close before navigating
 const DIALOG_WAIT_TIMEOUT = 500;

-/**
- * Merge into the current history entry's state, keeping what is already there.
- * Entries carry the app's own bookkeeping (`from`, `root`, dialog state), so
- * they must never be replaced wholesale.
- */
-export const updateHistoryState = (patch: Record<string, unknown>) => {
-  mainWindow.history.replaceState(
-    { ...mainWindow.history.state, ...patch },
-    ""
-  );
-};
-
-/**
- * Rewrite the URL of the current history entry without navigating and without
- * touching its state. For query parameter cleanup.
- */
-export const replaceCurrentUrl = (url: string) => {
-  mainWindow.history.replaceState(mainWindow.history.state, "", url);
-};
-
 /**
 * Stash a destination URL in the current history entry's state. If the page
 * is refreshed while a dialog is open, urlSyncMixin will navigate to this URL
@@ -45,7 +24,10 @@ export const replaceCurrentUrl = (url: string) => {
 * The current URL is not changed.
 */
 export const setRefreshUrl = (path: string) => {
-  updateHistoryState({ refreshUrl: path });
+  mainWindow.history.replaceState(
+    { ...mainWindow.history.state, refreshUrl: path },
+    ""
+  );
 };

 /**
@@ -81,32 +63,37 @@ export const navigate = async (path: string, options?: NavigateOptions) => {
  }
  const replace = options?.replace || false;

-  if (__DEMO__ && !path.includes("#")) {
-    // The demo routes with the hash instead of the pathname. Resolve the
-    // path like the browser would do for pushState, and keep the query
-    // parameters in the URL query instead of inside the hash.
-    const url = new URL(
-      path,
-      `${mainWindow.location.origin}${mainWindow.location.hash.substring(1)}`
-    );
-    path = `${mainWindow.location.pathname}${url.search}#${url.pathname}`;
-  }
-
-  const { history } = mainWindow;
-
-  if (replace) {
-    // A replaced entry keeps its predecessor, so it keeps `from`.
-    const { root, from } = history.state ?? {};
-    const state = root ? { root: true } : (options?.data ?? null);
-    history.replaceState(
-      from === undefined ? state : { ...state, from },
+  if (__DEMO__) {
+    if (!path.includes("#")) {
+      // The demo routes with the hash instead of the pathname. Resolve the
+      // path like the browser would do for pushState, and keep the query
+      // parameters in the URL query instead of inside the hash.
+      const url = new URL(
+        path,
+        `${mainWindow.location.origin}${mainWindow.location.hash.substring(1)}`
+      );
+      path = `${mainWindow.location.pathname}${url.search}#${url.pathname}`;
+    }
+    if (replace) {
+      mainWindow.history.replaceState(
+        mainWindow.history.state?.root
+          ? { root: true }
+          : (options?.data ?? null),
+        "",
+        path
+      );
+    } else {
+      mainWindow.history.pushState(options?.data ?? null, "", path);
+    }
+  } else if (replace) {
+    mainWindow.history.replaceState(
+      mainWindow.history.state?.root ? { root: true } : (options?.data ?? null),
      "",
      path
    );
  } else {
-    history.pushState({ ...options?.data, from: currentPath() }, "", path);
+    mainWindow.history.pushState(options?.data ?? null, "", path);
  }
-
  fireEvent(mainWindow, "location-changed", {
    replace,
  });
@@ -114,17 +101,8 @@ export const navigate = async (path: string, options?: NavigateOptions) => {
 };

 /**
- * Whether the previous history entry is a page this app navigated away from.
- * `history.length` cannot answer this: a login redirect goes through
- * `location.assign`, which leaves /auth/authorize right behind the requested
- * page, and going back there would bounce the user out of the app.
- */
-export const canGoBack = (): boolean =>
-  mainWindow.history.state?.from !== undefined;
-
-/**
- * Navigate back to the page we came from, falling back to a path when the
- * previous entry is not ours (deep link, login redirect, fresh tab).
+ * Navigate back in history, with fallback to a default path if no history exists.
+ * This prevents a user from getting stuck when they navigate directly to a page with no history.
 */
 export const goBack = async (fallbackPath?: string): Promise<void> => {
  const canProceed = await ensureDialogsClosed(Date.now());
@@ -132,12 +110,14 @@ export const goBack = async (fallbackPath?: string): Promise<void> => {
    return;
  }

-  // Read after closing dialogs: their history entries are popped by then, so
-  // this is the state of the page entry.
-  if (canGoBack()) {
-    mainWindow.history.back();
+  // Check if we have history to go back to
+  const { history } = mainWindow;
+  if (history.length > 1) {
+    history.back();
    return;
  }

-  navigate(fallbackPath || "/", { replace: true });
+  // No history available, navigate to fallback path
+  const fallback = fallbackPath || "/";
+  navigate(fallback, { replace: true });
 };
@@ -1,10 +0,0 @@
-import { mainWindow } from "../dom/get_main_window";
-
-/**
- * The path of the page currently shown by the app. The demo routes with the
- * hash instead of the pathname, see navigate().
- */
-export const currentPath = (): string =>
-  __DEMO__
-    ? mainWindow.location.hash.substring(1)
-    : mainWindow.location.pathname;
@@ -40,7 +40,7 @@ import {
  getEntityEntryContext,
 } from "../../common/entity/context/get_entity_context";
 import { shouldHandleRequestSelectedEvent } from "../../common/mwc/handle-request-selected-event";
-import { navigate, updateHistoryState } from "../../common/navigate";
+import { navigate } from "../../common/navigate";
 import type { LocalizeKeys } from "../../common/translations/localize";
 import { computeRTL } from "../../common/util/compute_rtl";
 import { withViewTransition } from "../../common/util/view-transition";
@@ -268,12 +268,16 @@ export class MoreInfoDialog extends DirtyStateProviderMixin<
  }

  private _setView(view: MoreInfoView) {
-    updateHistoryState({
-      dialogParams: {
-        ...history.state?.dialogParams,
-        view,
+    history.replaceState(
+      {
+        ...history.state,
+        dialogParams: {
+          ...history.state?.dialogParams,
+          view,
+        },
      },
-    });
+      ""
+    );
    this._currView = view;
  }

@@ -4,7 +4,6 @@ import { customElement, eventOptions, property } from "lit/decorators";
 import { classMap } from "lit/directives/class-map";
 import { restoreScroll } from "../common/decorators/restore-scroll";
 import type { HASSDomTargetEvent } from "../common/dom/fire_event";
-import { isNavigationClick } from "../common/dom/is-navigation-click";
 import { goBack } from "../common/navigate";
 import { sanitizeNavigationPath } from "../common/url/sanitize-navigation-path";
 import "../components/ha-icon-button-arrow-prev";
@@ -38,14 +37,19 @@ class HassSubpage extends LitElement {
      <div class="toolbar ${classMap({ narrow: this.narrow })}">
        <div class="toolbar-content">
          ${
-            this.mainPage || (!backPath && history.state?.root)
+            this.mainPage || history.state?.root
              ? html`<ha-menu-button></ha-menu-button>`
-              : html`
-                  <ha-icon-button-arrow-prev
-                    .href=${backPath}
-                    @click=${this._backTapped}
-                  ></ha-icon-button-arrow-prev>
-                `
+              : backPath
+                ? html`
+                    <ha-icon-button-arrow-prev
+                      href=${backPath}
+                    ></ha-icon-button-arrow-prev>
+                  `
+                : html`
+                    <ha-icon-button-arrow-prev
+                      @click=${this._backTapped}
+                    ></ha-icon-button-arrow-prev>
+                  `
          }

          <div class="main-title">
@@ -75,21 +79,12 @@ class HassSubpage extends LitElement {
    this._savedScrollPos = (e.target as HTMLDivElement).scrollTop;
  }

-  private _backTapped(ev: MouseEvent): void {
-    const backPath = sanitizeNavigationPath(this.backPath);
-
-    // Middle click, ctrl and cmd open the parent in a new tab, let the anchor
-    // handle those.
-    if (backPath && !isNavigationClick(ev)) {
-      return;
-    }
-
+  private _backTapped(): void {
    if (this.backCallback) {
      this.backCallback();
      return;
    }
-
-    goBack(backPath);
+    goBack();
  }

  static get styles(): CSSResultGroup {
@@ -175,12 +175,17 @@ export class HassTabsSubpage extends LitElement {
            ${
              this.mainPage || (!backPath && history.state?.root)
                ? html`<ha-menu-button></ha-menu-button>`
-                : html`
-                    <ha-icon-button-arrow-prev
-                      .href=${backPath}
-                      @click=${this._backTapped}
-                    ></ha-icon-button-arrow-prev>
-                  `
+                : backPath
+                  ? html`
+                      <ha-icon-button-arrow-prev
+                        .href=${backPath}
+                      ></ha-icon-button-arrow-prev>
+                    `
+                  : html`
+                      <ha-icon-button-arrow-prev
+                        @click=${this._backTapped}
+                      ></ha-icon-button-arrow-prev>
+                    `
            }
            ${
              this._narrow || !this.showTabs
@@ -241,21 +246,12 @@ export class HassTabsSubpage extends LitElement {
    this._content.focus({ preventScroll: true });
  }

-  private _backTapped(ev: MouseEvent): void {
-    const backPath = sanitizeNavigationPath(this.backPath);
-
-    // Middle click, ctrl and cmd open the parent in a new tab, let the anchor
-    // handle those.
-    if (backPath && !isNavigationClick(ev)) {
-      return;
-    }
-
+  private _backTapped(): void {
    if (this.backCallback) {
      this.backCallback();
      return;
    }
-
-    goBack(backPath);
+    goBack();
  }

  private _isActiveTabPath(tabPath: string, currentPath: string): boolean {
@@ -644,7 +644,6 @@ class HaConfigAreaPage extends LitElement {
      <hass-subpage
        .hass=${this.hass}
        .narrow=${this.narrow}
-        back-path="/config/areas/dashboard"
        .header=${html`${
          area.icon
            ? html`<ha-icon
@@ -86,6 +86,8 @@ export class HaConfigAreasDashboard extends LitElement {

  @state() private _hierarchy?: AreasFloorHierarchy;

+  private _searchParms = new URLSearchParams(window.location.search);
+
  private _blockHierarchyUpdate = false;

  private _blockHierarchyUpdateTimeout?: number;
@@ -166,7 +168,9 @@ export class HaConfigAreasDashboard extends LitElement {
      <hass-tabs-subpage
        .hass=${this.hass}
        .isWide=${this.isWide}
-        back-path="/config"
+        .backPath=${
+          this._searchParms.has("historyBack") ? undefined : "/config"
+        }
        .tabs=${configSections.areas}
        .route=${this.route}
        has-fab
@@ -443,7 +443,9 @@ class HaAutomationPicker extends SubscribeMixin(LitElement) {
      <hass-tabs-subpage-data-table
        .hass=${this.hass}
        .narrow=${this.narrow}
-        back-path="/config"
+        .backPath=${
+          this._searchParms.has("historyBack") ? undefined : "/config"
+        }
        id="entity_id"
        .route=${this.route}
        .tabs=${configSections.automations}
@@ -14,7 +14,7 @@ import { css, html, LitElement, nothing } from "lit";
 import { customElement, property, query, state } from "lit/decorators";
 import { isComponentLoaded } from "../../../common/config/is_component_loaded";
 import { fireEvent } from "../../../common/dom/fire_event";
-import { navigate, replaceCurrentUrl } from "../../../common/navigate";
+import { navigate } from "../../../common/navigate";
 import { computeRTL } from "../../../common/util/compute_rtl";
 import "../../../components/ha-button";
 import "../../../components/ha-dropdown";
@@ -110,7 +110,6 @@ export class HaAutomationTrace extends LitElement {
      <hass-subpage
        .hass=${this.hass}
        .narrow=${this.narrow}
-        back-path="/config/automation/dashboard"
        .header=${title}
        .scrollable=${this.narrow}
      >
@@ -453,7 +452,11 @@ export class HaAutomationTrace extends LitElement {
      if (runId) {
        const params = new URLSearchParams(location.search);
        params.delete("run_id");
-        replaceCurrentUrl(`${location.pathname}?${params.toString()}`);
+        history.replaceState(
+          null,
+          "",
+          `${location.pathname}?${params.toString()}`
+        );
      }

      await showAlertDialog(this, {
@@ -11,7 +11,6 @@ import { property, query, state } from "lit/decorators";
 import { classMap } from "lit/directives/class-map";
 import { storage } from "../../../common/decorators/storage";
 import { fireEvent } from "../../../common/dom/fire_event";
-import { replaceCurrentUrl } from "../../../common/navigate";
 import { constructUrlCurrentPath } from "../../../common/url/construct-url";
 import {
  extractSearchParam,
@@ -172,7 +171,11 @@ export const ManualEditorMixin = <TConfig>(
    }

    protected clearParam(param: string) {
-      replaceCurrentUrl(constructUrlCurrentPath(removeSearchParam(param)));
+      window.history.replaceState(
+        null,
+        "",
+        constructUrlCurrentPath(removeSearchParam(param))
+      );
    }

    protected async openSidebar(ev: CustomEvent<SidebarConfig>) {
@@ -74,6 +74,8 @@ class HaConfigBackupOverview extends LitElement {

  @state() private _config?: BackupConfig;

+  private _searchParms = new URLSearchParams(window.location.search);
+
  protected willUpdate(changedProperties: PropertyValues<this>): void {
    super.willUpdate(changedProperties);
    if (changedProperties.has("config") && !this._config) {
@@ -204,7 +206,9 @@ class HaConfigBackupOverview extends LitElement {

    return html`
      <hass-subpage
-        back-path="/config/system"
+        .backPath=${
+          this._searchParms.has("historyBack") ? undefined : "/config/system"
+        }
        .hass=${this.hass}
        .narrow=${this.narrow}
        .header=${this.hass.localize("ui.panel.config.backup.overview.header")}
@@ -4,7 +4,6 @@ import { css, html, LitElement, nothing } from "lit";
 import { customElement, property, state } from "lit/decorators";
 import { isComponentLoaded } from "../../../common/config/is_component_loaded";
 import { fireEvent } from "../../../common/dom/fire_event";
-import { replaceCurrentUrl } from "../../../common/navigate";
 import { debounce } from "../../../common/util/debounce";
 import { nextRender } from "../../../common/util/render-status";
 import "../../../components/ha-alert";
@@ -119,7 +118,7 @@ class HaConfigBackupSettings extends LitElement {
  }

  private _clearHash() {
-    replaceCurrentUrl(window.location.pathname);
+    history.replaceState(null, "", window.location.pathname);
  }

  protected render() {
@@ -21,7 +21,6 @@ export class CloudForgotPassword extends LitElement {
      <hass-subpage
        .hass=${this.hass}
        .narrow=${this.narrow}
-        back-path="/config"
        .header=${this.hass.localize(
          "ui.panel.config.cloud.forgot_password.title"
        )}
@@ -45,7 +45,6 @@ export class CloudLoginPanel extends LitElement {
      <hass-subpage
        .hass=${this.hass}
        .narrow=${this.narrow}
-        back-path="/config"
        header="Home Assistant Cloud"
      >
        <ha-dropdown slot="toolbar-icon" @wa-select=${this._handleMenuAction}>
@@ -38,7 +38,6 @@ export class CloudRegister extends LitElement {
      <hass-subpage
        .hass=${this.hass}
        .narrow=${this.narrow}
-        back-path="/config"
        .header=${this.hass.localize("ui.panel.config.cloud.register.title")}
      >
        <div class="content">
@@ -66,6 +66,8 @@ class HaConfigSectionUpdates extends LitElement {

  @property({ type: Boolean }) public narrow = false;

+  @state() private _searchParms = new URLSearchParams(window.location.search);
+
  @state() private _showSkipped = false;

  @state() private _supervisorInfo?: HassioSupervisorInfo;
@@ -153,7 +155,9 @@ class HaConfigSectionUpdates extends LitElement {

    return html`
      <hass-subpage
-        back-path="/config/system"
+        .backPath=${
+          this._searchParms.has("historyBack") ? undefined : "/config/system"
+        }
        .hass=${this.hass}
        .narrow=${this.narrow}
        .header=${this.hass.localize("ui.panel.config.updates.caption")}
@@ -986,7 +986,6 @@ export class HaConfigDevicePage extends LitElement {
    return html`<hass-subpage
      .hass=${this.hass}
      .narrow=${this.narrow}
-      back-path="/config/devices/dashboard"
      .header=${deviceName}
    >
      <ha-tooltip for="edit-settings-button" slot="toolbar-icon">
@@ -23,7 +23,7 @@ import {
  PROTOCOL_INTEGRATIONS,
  protocolIntegrationPicked,
 } from "../../../common/integrations/protocolIntegrationPicked";
-import { navigate, updateHistoryState } from "../../../common/navigate";
+import { navigate } from "../../../common/navigate";
 import type { LocalizeFunc } from "../../../common/translations/localize";
 import {
  hasRejectedItems,
@@ -778,7 +778,9 @@ export class HaConfigDeviceDashboard extends LitElement {
      <hass-tabs-subpage-data-table
        .hass=${this.hass}
        .narrow=${this.narrow}
-        back-path="/config"
+        .backPath=${
+          this._searchParms.has("historyBack") ? undefined : "/config"
+        }
        .tabs=${configSections.devices}
        .route=${this.route}
        .searchLabel=${this.hass.localize(
@@ -1041,7 +1043,7 @@ export class HaConfigDeviceDashboard extends LitElement {

  private _handleSearchChange(ev: CustomEvent) {
    this._filter = ev.detail.value;
-    updateHistoryState({ filter: this._filter });
+    history.replaceState({ filter: this._filter }, "");
  }

  private _addDevice() {
@@ -78,6 +78,8 @@ class HaConfigEnergy extends LitElement {

  @property({ attribute: false }) public route!: Route;

+  @state() private _searchParms = new URLSearchParams(window.location.search);
+
  @state() private _info?: EnergyInfo;

  @state() private _preferences?: EnergyPreferences;
@@ -124,7 +126,11 @@ class HaConfigEnergy extends LitElement {
    return html`
      <hass-tabs-subpage
        .hass=${this.hass}
-        back-path="/config/lovelace/dashboards"
+        .backPath=${
+          this._searchParms.has("historyBack")
+            ? undefined
+            : "/config/lovelace/dashboards"
+        }
        .route=${this.route}
        .tabs=${TABS}
      >
@@ -39,7 +39,6 @@ import {
  PROTOCOL_INTEGRATIONS,
  protocolIntegrationPicked,
 } from "../../../common/integrations/protocolIntegrationPicked";
-import { updateHistoryState } from "../../../common/navigate";
 import { slugify } from "../../../common/string/slugify";
 import type { LocalizeFunc } from "../../../common/translations/localize";
 import {
@@ -811,7 +810,9 @@ export class HaConfigEntities extends LitElement {
      <hass-tabs-subpage-data-table
        .hass=${this.hass}
        .narrow=${this.narrow}
-        back-path="/config"
+        .backPath=${
+          this._searchParms.has("historyBack") ? undefined : "/config"
+        }
        .route=${this.route}
        .tabs=${configSections.devices}
        .columns=${this._columns(this.hass.localize, filteredEntities)}
@@ -1245,7 +1246,7 @@ export class HaConfigEntities extends LitElement {

  private _handleSearchChange(ev: CustomEvent) {
    this._filter = ev.detail.value;
-    updateHistoryState({ filter: this._filter });
+    history.replaceState({ filter: this._filter }, "");
  }

  private _handleSelectionChanged(
@@ -644,7 +644,9 @@ export class HaConfigHelpers extends SubscribeMixin(LitElement) {
      <hass-tabs-subpage-data-table
        .hass=${this.hass}
        .narrow=${this.narrow}
-        back-path="/config"
+        .backPath=${
+          this._searchParms.has("historyBack") ? undefined : "/config"
+        }
        .route=${this.route}
        .tabs=${configSections.devices}
        .searchLabel=${this.hass.localize(
@@ -373,11 +373,7 @@ class HaConfigIntegrationPage extends SubscribeMixin(LitElement) {
      : this._manifest?.documentation;

    return html`
-      <hass-subpage
-        .hass=${this.hass}
-        .narrow=${this.narrow}
-        back-path="/config/integrations/dashboard"
-      >
+      <hass-subpage .hass=${this.hass} .narrow=${this.narrow}>
        ${
          documentationLink
            ? html`
@@ -13,7 +13,7 @@ import {
  PROTOCOL_INTEGRATIONS,
  protocolIntegrationPicked,
 } from "../../../common/integrations/protocolIntegrationPicked";
-import { navigate, updateHistoryState } from "../../../common/navigate";
+import { navigate } from "../../../common/navigate";
 import { caseInsensitiveStringCompare } from "../../../common/string/compare";
 import { extractSearchParam } from "../../../common/url/search-params";
 import { nextRender } from "../../../common/util/render-status";
@@ -158,6 +158,8 @@ class HaConfigIntegrationsDashboard extends KeyboardShortcutMixin(
    window.location.hash.substring(1)
  );

+  @state() private _searchParams = new URLSearchParams(window.location.search);
+
  @state() private _filter: string = history.state?.filter || "";

  @state() private _logInfos?: Record<string, IntegrationLogInfo>;
@@ -501,7 +503,9 @@ class HaConfigIntegrationsDashboard extends KeyboardShortcutMixin(
    return html`
      <hass-tabs-subpage
        .hass=${this.hass}
-        back-path="/config"
+        .backPath=${
+          this._searchParams.has("historyBack") ? undefined : "/config"
+        }
        .route=${this.route}
        .tabs=${configSections.devices}
        has-fab
@@ -858,7 +862,7 @@ class HaConfigIntegrationsDashboard extends KeyboardShortcutMixin(

  private _handleSearchChange(ev: InputEvent) {
    this._filter = (ev.target as HaInputSearch).value ?? "";
-    updateHistoryState({ filter: this._filter });
+    history.replaceState({ filter: this._filter }, "");
  }

  private async _highlightEntry() {
@@ -95,7 +95,6 @@ export class DHCPConfigPanel extends SubscribeMixin(LitElement) {
        .hass=${this.hass}
        .narrow=${this.narrow}
        .route=${this.route}
-        back-path="/config/integrations/integration/dhcp"
        .columns=${this._columns(this.hass.localize)}
        .data=${this._dataWithIds(this._data)}
        .noDataText=${this.hass.localize(
@@ -61,11 +61,7 @@ export class MQTTConfigPanel extends LitElement {

  protected render(): TemplateResult {
    return html`
-      <hass-subpage
-        .narrow=${this.narrow}
-        .hass=${this.hass}
-        back-path="/config/integrations/integration/mqtt"
-      >
+      <hass-subpage .narrow=${this.narrow} .hass=${this.hass}>
        <div class="content">
          <ha-card
            .header=${this.hass.localize("ui.panel.config.mqtt.settings_title")}
@@ -99,7 +99,6 @@ export class SSDPConfigPanel extends SubscribeMixin(LitElement) {
        .hass=${this.hass}
        .narrow=${this.narrow}
        .route=${this.route}
-        back-path="/config/integrations/integration/ssdp"
        .columns=${this._columns(this.hass.localize)}
        .initialGroupColumn=${this._activeGrouping}
        .initialCollapsedGroups=${this._activeCollapsed}
@@ -106,7 +106,6 @@ export class ZeroconfConfigPanel extends SubscribeMixin(LitElement) {
        .hass=${this.hass}
        .narrow=${this.narrow}
        .route=${this.route}
-        back-path="/config/integrations/integration/zeroconf"
        .columns=${this._columns(this.hass.localize)}
        .initialGroupColumn=${this._activeGrouping}
        .initialCollapsedGroups=${this._activeCollapsed}
@@ -76,7 +76,6 @@ class ZHAAddDevicesPage extends LitElement {
      <hass-subpage
        .hass=${this.hass}
        .narrow=${this.narrow}
-        back-path="/config/zha/dashboard"
        .header=${this.hass.localize("ui.panel.config.zha.add_device")}
      >
        <ha-button
@@ -55,7 +55,6 @@ export class ZHANetworkVisualizationPage extends LitElement {
      <hass-subpage
        .hass=${this.hass}
        .narrow=${this.narrow}
-        back-path="/config/zha/dashboard"
        .header=${this.hass.localize(
          "ui.panel.config.zha.visualization.header"
        )}
@@ -34,12 +34,7 @@ class ZWaveJSConfigEntryPicker extends LitElement {

    if (this._configEntries.length === 0) {
      return html`
-        <hass-subpage
-          header="Z-Wave"
-          .narrow=${this.narrow}
-          .hass=${this.hass}
-          back-path="/config/integrations/integration/zwave_js"
-        >
+        <hass-subpage header="Z-Wave" .narrow=${this.narrow} .hass=${this.hass}>
          <div class="content">
            <ha-card>
              <div class="card-content">
@@ -56,12 +51,7 @@ class ZWaveJSConfigEntryPicker extends LitElement {
    }

    return html`
-      <hass-subpage
-        header="Z-Wave"
-        .narrow=${this.narrow}
-        .hass=${this.hass}
-        back-path="/config/integrations/integration/zwave_js"
-      >
+      <hass-subpage header="Z-Wave" .narrow=${this.narrow} .hass=${this.hass}>
        <div class="content">
          <ha-card
            .header=${this.hass.localize(
@@ -175,7 +175,6 @@ export class HaConfigLovelaceResources extends LitElement {
        .hass=${this.hass}
        .narrow=${this.narrow}
        .route=${this.route}
-        back-path="/config/lovelace/dashboards"
        .tabs=${lovelaceResourcesTabs}
        .columns=${this._columns(this.hass.language, this.hass.localize)}
        .data=${this._resources}
@@ -32,6 +32,8 @@ class HaConfigRepairsDashboard extends SubscribeMixin(LitElement) {

  @state() private _repairsIssues: RepairsIssue[] = [];

+  @state() private _searchParms = new URLSearchParams(window.location.search);
+
  @state() private _showIgnored = false;

  private _getFilteredIssues = memoizeOne(
@@ -75,7 +77,9 @@ class HaConfigRepairsDashboard extends SubscribeMixin(LitElement) {

    return html`
      <hass-subpage
-        back-path="/config/system"
+        .backPath=${
+          this._searchParms.has("historyBack") ? undefined : "/config/system"
+        }
        .hass=${this.hass}
        .narrow=${this.narrow}
        .header=${this.hass.localize("ui.panel.config.repairs.caption")}
@@ -459,7 +459,9 @@ class HaSceneDashboard extends SubscribeMixin(LitElement) {
      <hass-tabs-subpage-data-table
        .hass=${this.hass}
        .narrow=${this.narrow}
-        back-path="/config"
+        .backPath=${
+          this._searchParms.has("historyBack") ? undefined : "/config"
+        }
        .route=${this.route}
        .tabs=${configSections.automations}
        .searchLabel=${this.hass.localize(
@@ -430,7 +430,9 @@ class HaScriptPicker extends SubscribeMixin(LitElement) {
      <hass-tabs-subpage-data-table
        .hass=${this.hass}
        .narrow=${this.narrow}
-        back-path="/config"
+        .backPath=${
+          this._searchParms.has("historyBack") ? undefined : "/config"
+        }
        .route=${this.route}
        .tabs=${configSections.automations}
        .searchLabel=${this.hass.localize(
@@ -14,7 +14,7 @@ import { css, html, LitElement, nothing } from "lit";
 import { customElement, property, query, state } from "lit/decorators";
 import { isComponentLoaded } from "../../../common/config/is_component_loaded";
 import { fireEvent } from "../../../common/dom/fire_event";
-import { navigate, replaceCurrentUrl } from "../../../common/navigate";
+import { navigate } from "../../../common/navigate";
 import "../../../components/ha-button";
 import "../../../components/ha-dropdown";
 import type { HaDropdownSelectEvent } from "../../../components/ha-dropdown";
@@ -106,7 +106,6 @@ export class HaScriptTrace extends LitElement {
      <hass-subpage
        .hass=${this.hass}
        .narrow=${this.narrow}
-        back-path="/config/script/dashboard"
        .header=${title}
        .scrollable=${this.narrow}
      >
@@ -434,7 +433,11 @@ export class HaScriptTrace extends LitElement {
      if (runId) {
        const params = new URLSearchParams(location.search);
        params.delete("run_id");
-        replaceCurrentUrl(`${location.pathname}?${params.toString()}`);
+        history.replaceState(
+          null,
+          "",
+          `${location.pathname}?${params.toString()}`
+        );
      }

      await showAlertDialog(this, {
@@ -128,7 +128,6 @@ class AssistDevicesPage extends LitElement {
      <hass-subpage
        .hass=${this.hass}
        .narrow=${this.narrow}
-        back-path="/config/voice-assistants/assistants"
        .header=${this.hass.localize(
          "ui.panel.config.voice_assistants.assistants.pipeline.devices.title"
        )}
@@ -51,7 +51,6 @@ export class AssistPipelineDebug extends LitElement {
    return html`<hass-subpage
      .narrow=${this.narrow}
      .hass=${this.hass}
-      back-path="/config/voice-assistants/debug"
      .header=${this.hass.localize(
        "ui.panel.config.voice_assistants.debug.header"
      )}
@@ -60,7 +60,6 @@ export class AssistPipelineRunDebug extends LitElement {
      <hass-subpage
        .narrow=${this.narrow}
        .hass=${this.hass}
-        back-path="/config/voice-assistants/assistants"
        .header=${this.hass.localize(
          "ui.panel.config.voice_assistants.debug.pipeline.header"
        )}
@@ -29,6 +29,8 @@ export class HaConfigVoiceAssistantsAssistants extends LitElement {

  @property({ attribute: false }) public route!: Route;

+  private _searchParms = new URLSearchParams(window.location.search);
+
  protected render() {
    if (!this.hass) {
      return html`<hass-loading-screen></hass-loading-screen>`;
@@ -37,7 +39,9 @@ export class HaConfigVoiceAssistantsAssistants extends LitElement {
    return html`
      <hass-tabs-subpage
        .hass=${this.hass}
-        back-path="/config"
+        .backPath=${
+          this._searchParms.has("historyBack") ? undefined : "/config"
+        }
        .route=${this.route}
        .tabs=${voiceAssistantTabs}
      >
@@ -492,7 +492,9 @@ export class VoiceAssistantsExpose extends LitElement {
      <hass-tabs-subpage-data-table
        .hass=${this.hass}
        .narrow=${this.narrow}
-        back-path="/config"
+        .backPath=${
+          this._searchParms.has("historyBack") ? undefined : "/config"
+        }
        .route=${this.route}
        .tabs=${voiceAssistantTabs}
        .columns=${this._columns(
@@ -57,6 +57,8 @@ export class HaConfigZone extends SubscribeMixin(LitElement) {

  @property({ attribute: false }) public route!: Route;

+  @state() private _searchParms = new URLSearchParams(window.location.search);
+
  @state() private _storageItems?: Zone[];

  @state() private _stateItems?: HassEntity[];
@@ -246,7 +248,9 @@ export class HaConfigZone extends SubscribeMixin(LitElement) {
      <hass-tabs-subpage
        .hass=${this.hass}
        .route=${this.route}
-        back-path="/config"
+        .backPath=${
+          this._searchParms.has("historyBack") ? undefined : "/config"
+        }
        .tabs=${configSections.areas}
        has-fab
      >
@@ -4,7 +4,7 @@ import type { PropertyValues, TemplateResult } from "lit";
 import { html, LitElement } from "lit";
 import { customElement, property, state } from "lit/decorators";
 import memoizeOne from "memoize-one";
-import { navigate, replaceCurrentUrl } from "../../common/navigate";
+import { navigate } from "../../common/navigate";
 import type { LocalizeFunc } from "../../common/translations/localize";
 import { constructUrlCurrentPath } from "../../common/url/construct-url";
 import {
@@ -509,7 +509,9 @@ export class LovelacePanel extends LitElement {
    };

    if ("editMode" in props) {
-      replaceCurrentUrl(
+      window.history.replaceState(
+        null,
+        "",
        constructUrlCurrentPath(
          props.editMode
            ? addSearchParam({ edit: "1" })
@@ -28,7 +28,7 @@ import { isComponentLoaded } from "../../common/config/is_component_loaded";
 import { UndoRedoController } from "../../common/controllers/undo-redo-controller";
 import { fireEvent } from "../../common/dom/fire_event";
 import { isNavigationClick } from "../../common/dom/is-navigation-click";
-import { goBack, navigate, replaceCurrentUrl } from "../../common/navigate";
+import { goBack, navigate } from "../../common/navigate";
 import type { LocalizeKeys } from "../../common/translations/localize";
 import { constructUrlCurrentPath } from "../../common/url/construct-url";
 import { sanitizeNavigationPath } from "../../common/url/sanitize-navigation-path";
@@ -677,7 +677,11 @@ class HUIRoot extends LitElement {
    );

  private _clearParam(param: string) {
-    replaceCurrentUrl(constructUrlCurrentPath(removeSearchParam(param)));
+    window.history.replaceState(
+      null,
+      "",
+      constructUrlCurrentPath(removeSearchParam(param))
+    );
  }

  protected firstUpdated(changedProps: PropertyValues<this>) {
@@ -890,10 +894,22 @@ class HUIRoot extends LitElement {

  private _goBack(): void {
    const views = this.lovelace?.config.views ?? [];
-    // Falling back to the first view only makes sense when it is a real view.
-    const fallbackPath = views[0]?.subview ? undefined : this.route?.prefix;
+    const curViewConfig =
+      typeof this._curView === "number" ? views[this._curView] : undefined;

-    goBack(this._backPath ?? fallbackPath);
+    const backPath = sanitizeNavigationPath(
+      curViewConfig?.back_path ?? this.backPath
+    );
+
+    if (backPath) {
+      navigate(backPath, { replace: true });
+    } else if (history.length > 1) {
+      goBack();
+    } else if (!views[0].subview) {
+      navigate(this.route!.prefix, { replace: true });
+    } else {
+      navigate("/");
+    }
  }

  private _handleBackClick(ev: MouseEvent): void {
@@ -9,7 +9,6 @@ import { repeat } from "lit/directives/repeat";
 import { styleMap } from "lit/directives/style-map";
 import memoizeOne from "memoize-one";
 import { clamp } from "../../../common/number/clamp";
-import { updateHistoryState } from "../../../common/navigate";
 import "../../../components/ha-icon-button";
 import "../../../components/ha-ripple";
 import "../../../components/ha-sortable";
@@ -495,7 +494,10 @@ export class SectionsView extends LitElement implements LovelaceViewElement {
    this._sidebarTabActive = !this._sidebarTabActive;

    // Add sidebar state to history
-    updateHistoryState({ sidebar: this._sidebarTabActive });
+    window.history.replaceState(
+      { ...window.history.state, sidebar: this._sidebarTabActive },
+      ""
+    );

    // Restore scroll position after view updates
    this.updateComplete.then(() => {
@@ -4,7 +4,6 @@ import { css, html, LitElement, nothing } from "lit";
 import { customElement, property, state } from "lit/decorators";
 import { isComponentLoaded } from "../../common/config/is_component_loaded";
 import { fireEvent } from "../../common/dom/fire_event";
-import { replaceCurrentUrl } from "../../common/navigate";
 import { nextRender } from "../../common/util/render-status";
 import "../../components/ha-button";
 import "../../components/ha-card";
@@ -91,7 +90,7 @@ class HaProfileSectionGeneral extends LitElement {
  }

  private _clearHash() {
-    replaceCurrentUrl(window.location.pathname);
+    history.replaceState(null, "", window.location.pathname);
  }

  protected render(): TemplateResult {
@@ -2,7 +2,6 @@
 import type { ReactiveElement, PropertyValues } from "lit";
 import { fireEvent } from "../common/dom/fire_event";
 import { mainWindow } from "../common/dom/get_main_window";
-import { updateHistoryState } from "../common/navigate";
 import { closeLastDialog } from "../dialogs/make-dialog-manager";
 import type { ProvideHassElement } from "../mixins/provide-hass-lit-mixin";
 import type { Constructor } from "../types";
@@ -21,7 +20,10 @@ export const urlSyncMixin = <
        public connectedCallback(): void {
          super.connectedCallback();
          if (mainWindow.history.length === 1) {
-            updateHistoryState({ root: true });
+            mainWindow.history.replaceState(
+              { ...mainWindow.history.state, root: true },
+              ""
+            );
          }
          mainWindow.addEventListener("popstate", this._popstateChangeListener);
        }
@@ -0,0 +1,96 @@
+/**
+ * @vitest-environment node
+ */
+
+import { Buffer } from "node:buffer";
+import { Readable } from "node:stream";
+import { promisify } from "node:util";
+import { brotliCompress, constants } from "node:zlib";
+import { describe, expect, it } from "vitest";
+import brotli from "../../build-scripts/brotli.mjs";
+import { file, filler, run as runStream } from "./vinyl-stub.js";
+
+// What build-scripts/gulp/compress.js asks for.
+const PARAMS = {
+  [constants.BROTLI_PARAM_QUALITY]: constants.BROTLI_MAX_QUALITY,
+};
+
+const run = (files, options = { skipLarger: true, params: PARAMS }) =>
+  runStream(brotli(options), files);
+
+const compressInProcess = promisify(brotliCompress);
+
+describe("brotli", () => {
+  it("appends .br and matches zlib byte for byte", async () => {
+    const contents = filler(4096);
+    const [result] = await run([file("/out/app.js", contents)]);
+
+    expect(result.path).toBe("/out/app.js.br");
+    expect(result.contents).toEqual(
+      await compressInProcess(contents, { params: PARAMS })
+    );
+  });
+
+  it("returns contents as a Buffer, which vinyl requires", async () => {
+    const [result] = await run([file("/out/app.js", filler(1024))]);
+
+    expect(Buffer.isBuffer(result.contents)).toBe(true);
+  });
+
+  it("appends to the path rather than replacing the extension", async () => {
+    const [result] = await run([file("/out/nested/chunk.min.js", filler(500))]);
+
+    expect(result.path).toBe("/out/nested/chunk.min.js.br");
+  });
+
+  it("drops files that compression grows when skipLarger is set", async () => {
+    expect(await run([file("/out/tiny.js", filler(1))])).toEqual([]);
+  });
+
+  it("keeps files that compression grows when skipLarger is not set", async () => {
+    const [result] = await run([file("/out/tiny.js", filler(1))], {
+      params: PARAMS,
+    });
+
+    expect(result.path).toBe("/out/tiny.js.br");
+  });
+
+  it("passes null files through", async () => {
+    const [result] = await run([file("/out/adirectory", null)]);
+
+    expect(result.path).toBe("/out/adirectory");
+    expect(result.contents).toBeNull();
+  });
+
+  it("buffers stream-mode contents", async () => {
+    const contents = filler(600);
+    const [result] = await run([
+      file("/out/streamed.js", Readable.from([contents])),
+    ]);
+
+    expect(result.path).toBe("/out/streamed.js.br");
+    expect(result.contents).toEqual(
+      await compressInProcess(contents, { params: PARAMS })
+    );
+  });
+
+  it("handles more files than it keeps in flight", async () => {
+    const count = 40;
+    const files = Array.from({ length: count }, (_, index) =>
+      file(`/out/chunk${index}.js`, filler(200 + index))
+    );
+
+    const results = await run(files);
+
+    expect(results).toHaveLength(count);
+    expect(new Set(results.map((result) => result.path)).size).toBe(count);
+    await Promise.all(
+      results.map(async (result) => {
+        const index = Number(result.path.match(/chunk(\d+)/)[1]);
+        expect(result.contents).toEqual(
+          await compressInProcess(filler(200 + index), { params: PARAMS })
+        );
+      })
+    );
+  });
+});
@@ -0,0 +1,104 @@
+/**
+ * @vitest-environment node
+ */
+
+import { setImmediate } from "node:timers/promises";
+import { describe, expect, it } from "vitest";
+import { ParallelTransform } from "../../build-scripts/parallel-transform.mjs";
+import { run } from "./vinyl-stub.js";
+
+const defer = () => {
+  const handle = {};
+  handle.promise = new Promise((resolve, reject) => {
+    handle.resolve = resolve;
+    handle.reject = reject;
+  });
+  return handle;
+};
+
+describe("ParallelTransform", () => {
+  it("keeps `limit` handlers in flight and no more", async () => {
+    const pending = [];
+    let active = 0;
+    let peak = 0;
+
+    const stream = new ParallelTransform(3, () => {
+      active += 1;
+      peak = Math.max(peak, active);
+      const handle = defer();
+      pending.push(handle);
+      return handle.promise.then((result) => {
+        active -= 1;
+        return result;
+      });
+    });
+
+    const items = Array.from({ length: 10 }, (_, index) => `item${index}`);
+    const done = run(stream, items);
+
+    await setImmediate();
+    expect(pending).toHaveLength(3);
+
+    for (let index = 0; index < items.length; index += 1) {
+      pending[index].resolve(items[index]);
+      // eslint-disable-next-line no-await-in-loop -- releasing one job at a time is the point
+      await setImmediate();
+    }
+
+    expect(await done).toEqual(items);
+    expect(peak).toBe(3);
+  });
+
+  it("emits in completion order rather than input order", async () => {
+    const pending = new Map();
+    const stream = new ParallelTransform(3, (item) => {
+      const handle = defer();
+      pending.set(item, handle);
+      return handle.promise;
+    });
+
+    const done = run(stream, ["a", "b", "c"]);
+    await setImmediate();
+
+    ["c", "a", "b"].forEach((item) => pending.get(item).resolve(item));
+
+    expect(await done).toEqual(["c", "a", "b"]);
+  });
+
+  it("drops results the handler resolves to nothing for", async () => {
+    const stream = new ParallelTransform(2, async (item) =>
+      item === "skip" ? undefined : item
+    );
+
+    expect(await run(stream, ["a", "skip", "b"])).toEqual(["a", "b"]);
+  });
+
+  it("fails the stream when a handler rejects", async () => {
+    const stream = new ParallelTransform(2, async (item) => {
+      if (item === "bad") {
+        throw new Error("boom");
+      }
+      return item;
+    });
+
+    await expect(run(stream, ["a", "bad", "b"])).rejects.toThrow("boom");
+  });
+
+  it("does not finish until in-flight work completes", async () => {
+    const handle = defer();
+    let ended = false;
+
+    const stream = new ParallelTransform(2, () => handle.promise);
+    const done = run(stream, ["a"]).then((results) => {
+      ended = true;
+      return results;
+    });
+
+    await setImmediate();
+    expect(ended).toBe(false);
+
+    handle.resolve("a");
+
+    expect(await done).toEqual(["a"]);
+  });
+});
@@ -0,0 +1,26 @@
+import { Buffer } from "node:buffer";
+import { Readable } from "node:stream";
+
+// Stand-in for the vinyl files gulp.src yields in buffer mode.
+export const file = (path, contents) => ({
+  path,
+  contents,
+  isNull() {
+    return this.contents === null;
+  },
+  isStream() {
+    return this.contents instanceof Readable;
+  },
+});
+
+export const filler = (length) => Buffer.alloc(length, "a");
+
+export const run = (stream, files) =>
+  new Promise((resolve, reject) => {
+    const out = [];
+    stream.on("data", (result) => out.push(result));
+    stream.on("error", reject);
+    stream.on("end", () => resolve(out));
+    files.forEach((entry) => stream.write(entry));
+    stream.end();
+  });
@@ -7,6 +7,7 @@ import process from "node:process";
 import { Readable } from "node:stream";
 import gfxZopfli from "@gfx/zopfli";
 import { describe, expect, it } from "vitest";
+import { file, filler, run as runStream } from "./vinyl-stub.js";

 // Keep the pool small; it is created once, on the first factory call.
 process.env.ZOPFLI_WORKERS = "2";
@@ -15,28 +16,8 @@ const { default: zopfli } = await import("../../build-scripts/zopfli.mjs");

 const THRESHOLD = 150;

-// Stand-in for the vinyl files gulp.src yields in buffer mode.
-const file = (path, contents) => ({
-  path,
-  contents,
-  isNull() {
-    return this.contents === null;
-  },
-  isStream() {
-    return this.contents instanceof Readable;
-  },
-});
-
 const run = (files, options = { threshold: THRESHOLD }) =>
-  new Promise((resolve, reject) => {
-    const stream = zopfli(options);
-    const out = [];
-    stream.on("data", (result) => out.push(result));
-    stream.on("error", reject);
-    stream.on("end", () => resolve(out));
-    files.forEach((entry) => stream.write(entry));
-    stream.end();
-  });
+  runStream(zopfli(options), files);

 // What the old in-process plugin did, for byte-for-byte comparison.
 const gzipInProcess = (contents) =>
@@ -46,8 +27,6 @@ const gzipInProcess = (contents) =>
    );
  });

-const filler = (length) => Buffer.alloc(length, "a");
-
 describe("zopfli worker pool", () => {
  it("appends .gz and matches in-process zopfli byte for byte", async () => {
    const contents = filler(4096);
@@ -1,88 +0,0 @@
-import { beforeEach, describe, expect, it, vi } from "vitest";
-
-import { canGoBack, goBack, navigate } from "../../src/common/navigate";
-
-// navigate() closes open dialogs before touching history.
-vi.mock("../../src/dialogs/make-dialog-manager", () => ({
-  closeAllDialogs: vi.fn(async () => true),
-}));
-
-// Sets up a raw entry the way a document load does, which is exactly what the
-// helpers in common/navigate refuse to produce.
-const setEntry = (path: string, state: unknown = null) => {
-  window.history.replaceState(state, "", path);
-};
-
-describe("navigate", () => {
-  beforeEach(() => {
-    setEntry("/config");
-  });
-
-  it("stamps the path we came from on pushed entries", async () => {
-    await navigate("/config/devices/dashboard");
-
-    expect(window.location.pathname).toEqual("/config/devices/dashboard");
-    expect(window.history.state).toMatchObject({ from: "/config" });
-  });
-
-  it("keeps caller data alongside the stamp", async () => {
-    await navigate("/config/areas", { data: { scrollPosition: 42 } });
-
-    expect(window.history.state).toMatchObject({
-      scrollPosition: 42,
-      from: "/config",
-    });
-  });
-
-  it("keeps the stamp when replacing, the predecessor is unchanged", async () => {
-    await navigate("/config/cloud");
-    await navigate("/config/cloud/account", { replace: true });
-
-    expect(window.location.pathname).toEqual("/config/cloud/account");
-    expect(window.history.state).toMatchObject({ from: "/config" });
-  });
-
-  it("does not stamp an entry the app did not push", () => {
-    expect(window.history.state).toBeNull();
-    expect(canGoBack()).toBe(false);
-  });
-});
-
-describe("goBack", () => {
-  beforeEach(() => {
-    setEntry("/config/cloud/remote");
-    vi.restoreAllMocks();
-  });
-
-  it("goes back when we came from another page in the app", async () => {
-    const back = vi
-      .spyOn(window.history, "back")
-      .mockImplementation(() => undefined);
-    await navigate("/config/cloud/remote");
-
-    await goBack("/config/cloud/account");
-
-    expect(back).toHaveBeenCalledOnce();
-  });
-
-  it("falls back to the given path when the previous entry is not ours", async () => {
-    // A login redirect lands on the page through location.assign, leaving
-    // /auth/authorize behind: going back there would leave the app.
-    const back = vi
-      .spyOn(window.history, "back")
-      .mockImplementation(() => undefined);
-
-    await goBack("/config/cloud/account");
-
-    expect(back).not.toHaveBeenCalled();
-    expect(window.location.pathname).toEqual("/config/cloud/account");
-  });
-
-  it("falls back to the root when no path is given", async () => {
-    vi.spyOn(window.history, "back").mockImplementation(() => undefined);
-
-    await goBack();
-
-    expect(window.location.pathname).toEqual("/");
-  });
-});
@@ -28,7 +28,7 @@ afterEach(() => {
 describe("hass-subpage back path", () => {
  it("links to a path on the current origin", async () => {
    const backButton = await mount("/config/system");
-    expect(backButton!.href).toEqual("/config/system");
+    expect(backButton!.getAttribute("href")).toEqual("/config/system");
  });

  // eslint-disable-next-line no-script-url
@@ -36,7 +36,7 @@ describe("hass-subpage back path", () => {
    "does not link to %s",
    async (backPath) => {
      const backButton = await mount(backPath);
-      expect(backButton!.href).toBeUndefined();
+      expect(backButton!.hasAttribute("href")).toBe(false);
    }
  );
 });
@@ -9714,16 +9714,6 @@ __metadata:
  languageName: node
  linkType: hard

-"gulp-brotli@npm:3.0.0":
-  version: 3.0.0
-  resolution: "gulp-brotli@npm:3.0.0"
-  dependencies:
-    plugin-error: "npm:^1.0.1"
-    through2: "npm:^3.0.1"
-  checksum: 10/0eea1fc60ae7f256184155b61a30a916007d21d37234698d8cdb299f64f71b4d68ca3182528e7da5d71290079c32c0228573578b76f5af7af7230c31537ef9d2
-  languageName: node
-  linkType: hard
-
 "gulp-cli@npm:^3.1.0":
  version: 3.1.0
  resolution: "gulp-cli@npm:3.1.0"
@@ -9979,7 +9969,6 @@ __metadata:
    glob: "npm:13.0.6"
    globals: "npm:17.8.0"
    gulp: "npm:5.0.1"
-    gulp-brotli: "npm:3.0.0"
    gulp-json-transform: "npm:0.5.0"
    gulp-rename: "npm:2.1.0"
    hls.js: "npm:1.6.16"
@@ -12977,17 +12966,6 @@ __metadata:
  languageName: node
  linkType: hard

-"readable-stream@npm:2 || 3, readable-stream@npm:^3.4.0":
-  version: 3.6.2
-  resolution: "readable-stream@npm:3.6.2"
-  dependencies:
-    inherits: "npm:^2.0.3"
-    string_decoder: "npm:^1.1.1"
-    util-deprecate: "npm:^1.0.1"
-  checksum: 10/d9e3e53193adcdb79d8f10f2a1f6989bd4389f5936c6f8b870e77570853561c362bee69feca2bbb7b32368ce96a85504aa4cedf7cf80f36e6a9de30d64244048
-  languageName: node
-  linkType: hard
-
 "readable-stream@npm:^2.3.5, readable-stream@npm:~2.3.6":
  version: 2.3.8
  resolution: "readable-stream@npm:2.3.8"
@@ -13003,6 +12981,17 @@ __metadata:
  languageName: node
  linkType: hard

+"readable-stream@npm:^3.4.0":
+  version: 3.6.2
+  resolution: "readable-stream@npm:3.6.2"
+  dependencies:
+    inherits: "npm:^2.0.3"
+    string_decoder: "npm:^1.1.1"
+    util-deprecate: "npm:^1.0.1"
+  checksum: 10/d9e3e53193adcdb79d8f10f2a1f6989bd4389f5936c6f8b870e77570853561c362bee69feca2bbb7b32368ce96a85504aa4cedf7cf80f36e6a9de30d64244048
+  languageName: node
+  linkType: hard
+
 "readable-stream@npm:^4.7.0":
  version: 4.7.0
  resolution: "readable-stream@npm:4.7.0"
@@ -14561,16 +14550,6 @@ __metadata:
  languageName: node
  linkType: hard

-"through2@npm:^3.0.1":
-  version: 3.0.2
-  resolution: "through2@npm:3.0.2"
-  dependencies:
-    inherits: "npm:^2.0.4"
-    readable-stream: "npm:2 || 3"
-  checksum: 10/98bdffba8e877fd8beb2154adc4eb0d52fad281130f56f6e5d18f85d1e1aa528a7b27317b302eb5443f6636ab045d3c272e6dffc61d984775db284823b90532d
-  languageName: node
-  linkType: hard
-
 "time-stamp@npm:^1.0.0":
  version: 1.1.0
  resolution: "time-stamp@npm:1.1.0"