noImplicitAny, batch 6: the mpv helper typed without a forced reinstall (880 to 766)

CLAUDE.md

@@ -145,8 +145,9 @@ mpv host's installed copy, WSL): `docs/notes/local-pc.md`.
 - **SPLICER only processes `.mjs` and `.js`.** Code moved into a `.ts` file silently stops
   being spliced. Stay on `.mjs` plus JSDoc.
 - **A change to `native-host/faststream-mpv-host.mjs` or `install.ps1` raises the host's
-  version**: `HostVersion` there, `RequiredHostVersion` in `MpvBackend.mjs`, and the record
-  in `tests/unit/mpvHostVersion.test.mjs`, which fails until they agree.
+  version**: `HostVersion` there and the record in `tests/unit/mpvHostVersion.test.mjs`,
+  which fails until they agree; `RequiredHostVersion` in `MpvBackend.mjs` too only when the
+  extension needs the new host (a change with no new behaviour leaves it: no reinstall).
 - **A file with `// @ts-check` keeps it**, and is listed in
   `tests/unit/typeChecked.test.mjs`. `types/messages.d.ts` gets a message only after its
   real payload was read.

chrome/player/players/vm/VMPlayer.mjs

@@ -5,6 +5,10 @@ import {RequestUtils} from '../../utils/RequestUtils.mjs';
 import HLSPlayer from '../hls/HLSPlayer.mjs';
 
 export default class VMPlayer extends HLSPlayer {
+  /**
+   * @param {import('../../FastStreamClient.mjs').FastStreamClient} client - The player client the player talks through.
+   * @param {*} options - The player's options, passed unchanged to the base player.
+   */
   constructor(client, options) {
     super(client, options);
   }
@@ -37,6 +41,9 @@ export default class VMPlayer extends HLSPlayer {
     return 'https://player.vimeo.com/video/' + encodeURIComponent(path[1]) + (path[2] ? '/config' : '') + query;
   }
 
+  /**
+   * @param {import('../../VideoSource.mjs').VideoSource} source - The Vimeo source to play.
+   */
   async setSource(source) {
     try {
       const requestUrl = VMPlayer.vimeoRequestUrl(source.url);
@@ -48,13 +55,13 @@ export default class VMPlayer extends HLSPlayer {
       const isEmbed = !new URL(requestUrl).pathname.endsWith('/config');
       const hc = [];
       if (Array.isArray(source.headers)) {
-        source.headers.forEach((h) => {
+        source.headers.forEach(/** @type {(h: {name: string, value: string}) => void} */ ((h) => {
           hc.push({
             operation: 'set',
             header: h.name,
             value: h.value,
           });
-        });
+        }));
       } else {
         for (const key in source.headers) {
           if (Object.hasOwn(source.headers, key)) {
@@ -114,6 +121,9 @@ export default class VMPlayer extends HLSPlayer {
     return this.source;
   }
 
+  /**
+   * @param {string} html - The HTML of the Vimeo player page.
+   */
   extractVimeoHlsUrlFromIframePlayer(html) {
     const config = this.extractJsonConfig(html, 'window.playerConfig =');
 
@@ -124,6 +134,10 @@ export default class VMPlayer extends HLSPlayer {
     return config?.request?.files?.hls;
   }
 
+  /**
+   * @param {string} html - The HTML to search for the JSON config.
+   * @param {string} prefix - The text that marks where the JSON starts.
+   */
   extractJsonConfig(html, prefix) {
     const startIndex = html.indexOf(prefix);
     if (startIndex === -1) return null;

chrome/player/ui/VolumeControls.mjs

@@ -15,6 +15,7 @@ if (!EnvUtils.isWebAudioSupported()) {
 const VolumeSaveDelayMs = 500;
 
 export class VolumeControls extends EventEmitter {
+  /** @param {import('../FastStreamClient.mjs').FastStreamClient} client */
   constructor(client) {
     super();
     this.client = client;
@@ -61,6 +62,7 @@ export class VolumeControls extends EventEmitter {
     this.loadVolumeState();
   }
 
+  /** @param {number} volume */
   setVolume(volume, dontSave = false) {
     if (volume < 0) {
       volume = 0;
@@ -95,13 +97,15 @@ export class VolumeControls extends EventEmitter {
     }
   }
 
+  /** @param {MouseEvent} event */
   onVolumeBarMouseDown(event) {
     // Only the left button drags. A right-click's context menu takes the mouseup, and the
     // volume then followed the mouse until the next click.
     if (event.button !== 0) {
       return;
     }
 
+    /** @param {number} volumeBarX */
     const shiftVolume = (volumeBarX) => {
       const totalWidth = /** @type {HTMLElement} */ (DOMElements.volumeControlBar).clientWidth;
 
@@ -120,13 +124,14 @@ export class VolumeControls extends EventEmitter {
       }
     };
 
+    /** @param {MouseEvent|TouchEvent} event */
     const onVolumeBarMouseMove = (event) => {
       // No button held: it was let go where this drag never heard of it.
-      if (event.type === 'mousemove' && event.buttons === 0) {
+      if (event.type === 'mousemove' && /** @type {MouseEvent} */ (event).buttons === 0) {
         stopDrag();
         return;
       }
-      const currentX = event.clientX - WebUtils.getOffsetLeft(/** @type {HTMLElement} */ (DOMElements.volumeContainer)) - 10;
+      const currentX = /** @type {MouseEvent} */ (event).clientX - WebUtils.getOffsetLeft(/** @type {HTMLElement} */ (DOMElements.volumeContainer)) - 10;
       shiftVolume(currentX);
     };
 
@@ -138,10 +143,11 @@ export class VolumeControls extends EventEmitter {
       document.removeEventListener('mouseup', onVolumeBarMouseUp);
     };
 
+    /** @param {MouseEvent|TouchEvent} event */
     const onVolumeBarMouseUp = (event) => {
       stopDrag();
 
-      const currentX = event.clientX - WebUtils.getOffsetLeft(/** @type {HTMLElement} */ (DOMElements.volumeContainer)) - 10;
+      const currentX = /** @type {MouseEvent} */ (event).clientX - WebUtils.getOffsetLeft(/** @type {HTMLElement} */ (DOMElements.volumeContainer)) - 10;
 
       if (!isNaN(currentX)) {
         shiftVolume(currentX);
@@ -159,6 +165,7 @@ export class VolumeControls extends EventEmitter {
     event.stopPropagation();
   }
 
+  /** @param {number} volume */
   updateVolumeBar(volume) {
     const currentVolumeTag = /** @type {HTMLElement} */ (DOMElements.currentVolume);
     const muteButtonTag = /** @type {HTMLElement} */ (DOMElements.muteBtn);
@@ -192,7 +199,7 @@ export class VolumeControls extends EventEmitter {
     const state = await Utils.loadAndParseOptions('volumeState', {
       volume: 1,
     });
-    this.setVolume(state.volume, true);
+    this.setVolume(/** @type {{volume: number}} */ (state).volume, true);
   }
 
   /** Saves a volume change still waiting for its delay. */

chrome/player/ui/VpnPrompt.mjs

@@ -16,7 +16,7 @@ import {DOMElements} from './DOMElements.mjs';
  */
 export class VpnPrompt {
   /**
-   * @param {Object} client - The FastStreamClient.
+   * @param {import('../FastStreamClient.mjs').FastStreamClient} client - The FastStreamClient.
    */
   constructor(client) {
     this.client = client;
@@ -42,10 +42,10 @@ export class VpnPrompt {
   async check(source) {
     this.hide();
     this.source = source;
-    if (!EnvUtils.isExtension() || !source?.url) return;
+    if (!EnvUtils.isExtension() || !/** @type {{url: string}} */ (source)?.url) return;
     let status;
     try {
-      status = await chrome.runtime.sendMessage({type: MessageTypes.VPN_STATUS, url: source.url});
+      status = await chrome.runtime.sendMessage({type: MessageTypes.VPN_STATUS, url: /** @type {{url: string}} */ (source).url});
     } catch (e) {
       return;
     }

chrome/player/ui/audio/AbstractAudioModule.mjs

@@ -3,6 +3,9 @@ import {EventEmitter} from '../../modules/eventemitter.mjs';
 import {VirtualAudioNode} from './VirtualAudioNode.mjs';
 
 export class AbstractAudioModule extends EventEmitter {
+  /**
+   * @param {string} name
+   */
   constructor(name) {
     super();
     this.audioContext = null;

chrome/player/utils/BlobManager.mjs

@@ -5,7 +5,7 @@
 export class BlobManager {
   /**
    * Creates a blob from data and MIME type.
-   * @param {Array} data - The data to store in the blob.
+  * @param {Array<BlobPart>} data - The data to store in the blob.
    * @param {string} mimeType - The MIME type of the blob.
    * @return {Blob} The created blob.
    */

docs/notes/mpv.md

@@ -27,10 +27,12 @@ to it, and the result carries `hostOutdated`. That shows as "!" on the toolbar b
 in MPV mode with what to run in the tooltip (`tab.mpvHostOutdated`, persisted like
 `mpvError`, whose reason comes first), in the player's "Sent to mpv" message, and after
 "Test mpv connection". This replaced `mpv-host-changed.yml`'s e-mail. **Every change to
-the host file or to `install.ps1` raises both numbers by one**:
-`tests/unit/mpvHostVersion.test.mjs` records both files' SHA-256 beside the version and
-fails until `HostVersion`, `RequiredHostVersion` and the record agree (the failure prints
-the new hashes). The installer counts because `update-local.ps1` tells an installed host
+the host file or to `install.ps1` raises `HostVersion` by one**, and `RequiredHostVersion`
+with it only when the extension needs the new host (since 2026-10-23: a change that alters
+no behaviour, such as the host's types, has every installed host go on working, and nobody
+is asked to reinstall): `tests/unit/mpvHostVersion.test.mjs` records both files' SHA-256
+beside the version, fails until `HostVersion` and the record agree (the failure prints the
+new hashes), and checks `RequiredHostVersion <= HostVersion`. The installer counts because `update-local.ps1` tells an installed host
 from the repository's by the host file alone; a raised `HostVersion` changes that file. The
 extension changes with it, so such a push releases, Firefox updates the extension, and
 the next hand-off on the owner's PC shows the "!" until `update-local.cmd` (or

docs/notes/type-checking.md

@@ -46,10 +46,10 @@ is lowered with `pnpm run typecheck:strict -- --update`, so a typed file cannot
 unnoticed. `tests/unit/checkImplicitAny.test.mjs` covers the rules (each broken once, and
 caught), and an untyped parameter planted in a file at 0 failed the check with its line.
 
-The mpv host (`native-host/faststream-mpv-host.mjs`, 76 untyped places) is left out on
-purpose: any change to it raises `HostVersion` and `RequiredHostVersion`, and the add-on
-then has every user reinstall the helper, for comments that change no behaviour. It is
-typed the next time it changes for a real reason; until then the ratchet holds its count.
+The mpv host (`native-host/faststream-mpv-host.mjs`) was typed on 2026-10-23 (76 to 1
+untyped places) with `HostVersion` 20 and `RequiredHostVersion` left at 19: a change
+that alters no behaviour raises only the host's own version, so installed helpers go on
+working and nobody is asked to reinstall for comments (the owner's choice).
 
 ### The libraries' own types (2026-10-22)