Enable tsc alwaysStrict, strictBindCallApply, noImplicitThis (#9600)

* Enable tsc alwaysStrict

* Enable tsc strictBindCallApply

* Enable tsc noImplicitThis

* Add d.ts

* Improve types

* Add ?

* Increase coverage

* Improve coverage

package.json

@@ -212,7 +212,7 @@
     "stylelint": "^14.9.1",
     "stylelint-config-standard": "^26.0.0",
     "stylelint-scss": "^4.2.0",
-    "typescript": "4.7.4",
+    "typescript": "4.8.4",
     "walk": "^2.3.14"
   },
   "jest": {

src/@types/common.ts

@@ -24,15 +24,16 @@ export type Writeable<T> = { -readonly [P in keyof T]: T[P] };
 export type ComponentClass = keyof JSX.IntrinsicElements | JSXElementConstructor<any>;
 export type ReactAnyComponent = React.Component | React.ExoticComponent;
 
+// Utility type for string dot notation for accessing nested object properties
 // Based on https://stackoverflow.com/a/58436959
 type Join<K, P> = K extends string | number ?
     P extends string | number ?
         `${K}${"" extends P ? "" : "."}${P}`
         : never : never;
 
-type Prev = [never, 0, 1, 2, 3, 4, 5, 6, 7, 8, 9, 10, ...0[]];
+type Prev = [never, 0, 1, 2, 3, ...0[]];
 
-export type Leaves<T, D extends number = 5> = [D] extends [never] ? never : T extends object ?
+export type Leaves<T, D extends number = 3> = [D] extends [never] ? never : T extends object ?
     { [K in keyof T]-?: Join<K, Leaves<T[K], Prev[D]>> }[keyof T] : "";
 
 export type RecursivePartial<T> = {

src/@types/commonmark.ts

@@ -0,0 +1,52 @@
+/*
+Copyright 2022 The Matrix.org Foundation C.I.C.
+
+Licensed under the Apache License, Version 2.0 (the "License");
+you may not use this file except in compliance with the License.
+You may obtain a copy of the License at
+
+http://www.apache.org/licenses/LICENSE-2.0
+
+Unless required by applicable law or agreed to in writing, software
+distributed under the License is distributed on an "AS IS" BASIS,
+WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+See the License for the specific language governing permissions and
+limitations under the License.
+*/
+
+import * as commonmark from "commonmark";
+
+declare module "commonmark" {
+    export type Attr = [key: string, value: string];
+
+    export interface HtmlRenderer {
+        // As far as @types/commonmark is concerned, these are not public, so add them
+        // https://github.com/commonmark/commonmark.js/blob/master/lib/render/html.js#L272-L296
+        text: (this: commonmark.HtmlRenderer, node: commonmark.Node) => void;
+        html_inline: (this: commonmark.HtmlRenderer, node: commonmark.Node) => void;
+        html_block: (this: commonmark.HtmlRenderer, node: commonmark.Node) => void;
+        // softbreak: () => void; // This one can't be correctly specified as it is wrongly defined in @types/commonmark
+        linebreak: (this: commonmark.HtmlRenderer) => void;
+        link: (this: commonmark.HtmlRenderer, node: commonmark.Node, entering: boolean) => void;
+        image: (this: commonmark.HtmlRenderer, node: commonmark.Node, entering: boolean) => void;
+        emph: (this: commonmark.HtmlRenderer, node: commonmark.Node, entering: boolean) => void;
+        strong: (this: commonmark.HtmlRenderer, node: commonmark.Node, entering: boolean) => void;
+        paragraph: (this: commonmark.HtmlRenderer, node: commonmark.Node, entering: boolean) => void;
+        heading: (this: commonmark.HtmlRenderer, node: commonmark.Node, entering: boolean) => void;
+        code: (this: commonmark.HtmlRenderer, node: commonmark.Node) => void;
+        code_block: (this: commonmark.HtmlRenderer, node: commonmark.Node) => void;
+        thematic_break: (this: commonmark.HtmlRenderer, node: commonmark.Node) => void;
+        block_quote: (this: commonmark.HtmlRenderer, node: commonmark.Node, entering: boolean) => void;
+        list: (this: commonmark.HtmlRenderer, node: commonmark.Node, entering: boolean) => void;
+        item: (this: commonmark.HtmlRenderer, node: commonmark.Node, entering: boolean) => void;
+        custom_inline: (this: commonmark.HtmlRenderer, node: commonmark.Node, entering: boolean) => void;
+        custom_block: (this: commonmark.HtmlRenderer, node: commonmark.Node, entering: boolean) => void;
+        esc: (s: string) => string;
+        out: (this: commonmark.HtmlRenderer, text: string) => void;
+        tag: (this: commonmark.HtmlRenderer, name: string, attrs?: Attr[], selfClosing?: boolean) => void;
+        attrs: (this: commonmark.HtmlRenderer, node: commonmark.Node) => Attr[];
+        // These are inherited from the base Renderer
+        lit: (this: commonmark.HtmlRenderer, text: string) => void;
+        cr: (this: commonmark.HtmlRenderer) => void;
+    }
+}

src/Markdown.ts

@@ -15,6 +15,7 @@ See the License for the specific language governing permissions and
 limitations under the License.
 */
 
+import "./@types/commonmark"; // import better types than @types/commonmark
 import * as commonmark from 'commonmark';
 import { escape } from "lodash";
 import { logger } from 'matrix-js-sdk/src/logger';
@@ -26,17 +27,6 @@ const ALLOWED_HTML_TAGS = ['sub', 'sup', 'del', 'u'];
 // These types of node are definitely text
 const TEXT_NODES = ['text', 'softbreak', 'linebreak', 'paragraph', 'document'];
 
-// As far as @types/commonmark is concerned, these are not public, so add them
-interface CommonmarkHtmlRendererInternal extends commonmark.HtmlRenderer {
-    paragraph: (node: commonmark.Node, entering: boolean) => void;
-    link: (node: commonmark.Node, entering: boolean) => void;
-    html_inline: (node: commonmark.Node) => void; // eslint-disable-line camelcase
-    html_block: (node: commonmark.Node) => void; // eslint-disable-line camelcase
-    text: (node: commonmark.Node) => void;
-    out: (text: string) => void;
-    emph: (node: commonmark.Node) => void;
-}
-
 function isAllowedHtmlTag(node: commonmark.Node): boolean {
     if (node.literal != null &&
         node.literal.match('^<((div|span) data-mx-maths="[^"]*"|/(div|span))>$') != null) {
@@ -248,7 +238,7 @@ export default class Markdown {
     isPlainText(): boolean {
         const walker = this.parsed.walker();
 
-        let ev;
+        let ev: commonmark.NodeWalkingStep;
         while (ev = walker.next()) {
             const node = ev.node;
             if (TEXT_NODES.indexOf(node.type) > -1) {
@@ -278,7 +268,7 @@ export default class Markdown {
             // block quote ends up all on one line
             // (https://github.com/vector-im/element-web/issues/3154)
             softbreak: '<br />',
-        }) as CommonmarkHtmlRendererInternal;
+        });
 
         // Trying to strip out the wrapping <p/> causes a lot more complication
         // than it's worth, i think.  For instance, this code will go and strip
@@ -356,7 +346,7 @@ export default class Markdown {
      * which has no formatting.  Otherwise it emits HTML(!).
      */
     toPlaintext(): string {
-        const renderer = new commonmark.HtmlRenderer({ safe: false }) as CommonmarkHtmlRendererInternal;
+        const renderer = new commonmark.HtmlRenderer({ safe: false });
 
         renderer.paragraph = function(node: commonmark.Node, entering: boolean) {
             // as with toHTML, only append lines to paragraphs if there are

src/Notifier.ts

@@ -210,7 +210,7 @@ export const Notifier = {
         }
     },
 
-    start: function() {
+    start: function(this: typeof Notifier) {
         // do not re-bind in the case of repeated call
         this.boundOnEvent = this.boundOnEvent || this.onEvent.bind(this);
         this.boundOnSyncStateChange = this.boundOnSyncStateChange || this.onSyncStateChange.bind(this);
@@ -225,7 +225,7 @@ export const Notifier = {
         this.isSyncing = false;
     },
 
-    stop: function() {
+    stop: function(this: typeof Notifier) {
         if (MatrixClientPeg.get()) {
             MatrixClientPeg.get().removeListener(ClientEvent.Event, this.boundOnEvent);
             MatrixClientPeg.get().removeListener(RoomEvent.Receipt, this.boundOnRoomReceipt);
@@ -322,7 +322,7 @@ export const Notifier = {
         return SettingsStore.getValue("audioNotificationsEnabled");
     },
 
-    setPromptHidden: function(hidden: boolean, persistent = true) {
+    setPromptHidden: function(this: typeof Notifier, hidden: boolean, persistent = true) {
         this.toolbarHidden = hidden;
 
         hideNotificationsToast();
@@ -343,7 +343,7 @@ export const Notifier = {
                !this.isEnabled() && !this._isPromptHidden();
     },
 
-    _isPromptHidden: function() {
+    _isPromptHidden: function(this: typeof Notifier) {
         // Check localStorage for any such meta data
         if (global.localStorage) {
             return global.localStorage.getItem("notifications_hidden") === "true";
@@ -352,7 +352,7 @@ export const Notifier = {
         return this.toolbarHidden;
     },
 
-    onSyncStateChange: function(state: SyncState, prevState?: SyncState, data?: ISyncStateData) {
+    onSyncStateChange: function(this: typeof Notifier, state: SyncState, prevState?: SyncState, data?: ISyncStateData) {
         if (state === SyncState.Syncing) {
             this.isSyncing = true;
         } else if (state === SyncState.Stopped || state === SyncState.Error) {
@@ -368,7 +368,7 @@ export const Notifier = {
         }
     },
 
-    onEvent: function(ev: MatrixEvent) {
+    onEvent: function(this: typeof Notifier, ev: MatrixEvent) {
         if (!this.isSyncing) return; // don't alert for any messages initially
         if (ev.getSender() === MatrixClientPeg.get().getUserId()) return;
 

src/SlashCommands.tsx

@@ -111,7 +111,7 @@ export const CommandCategories = {
 
 export type RunResult = XOR<{ error: Error | ITranslatableError }, { promise: Promise<IContent | undefined> }>;
 
-type RunFn = ((roomId: string, args: string, cmd: string) => RunResult);
+type RunFn = ((this: Command, roomId: string, args: string) => RunResult);
 
 interface ICommandOpts {
     command: string;
@@ -129,9 +129,9 @@ interface ICommandOpts {
 export class Command {
     public readonly command: string;
     public readonly aliases: string[];
-    public readonly args: undefined | string;
+    public readonly args?: string;
     public readonly description: string;
-    public readonly runFn: undefined | RunFn;
+    public readonly runFn?: RunFn;
     public readonly category: string;
     public readonly hideCompletionAfterSpace: boolean;
     public readonly renderingTypes?: TimelineRenderingType[];
@@ -143,7 +143,7 @@ export class Command {
         this.aliases = opts.aliases || [];
         this.args = opts.args || "";
         this.description = opts.description;
-        this.runFn = opts.runFn;
+        this.runFn = opts.runFn?.bind(this);
         this.category = opts.category || CommandCategories.other;
         this.hideCompletionAfterSpace = opts.hideCompletionAfterSpace || false;
         this._isEnabled = opts.isEnabled;
@@ -188,7 +188,7 @@ export class Command {
             });
         }
 
-        return this.runFn.bind(this)(roomId, args);
+        return this.runFn(roomId, args);
     }
 
     public getUsage() {
@@ -1114,7 +1114,7 @@ export const Commands = [
         description: _td("Sends the given message coloured as a rainbow"),
         args: '<message>',
         runFn: function(roomId, args) {
-            if (!args) return reject(this.getUserId());
+            if (!args) return reject(this.getUsage());
             return successSync(ContentHelpers.makeHtmlMessage(args, textToHtmlRainbow(args)));
         },
         category: CommandCategories.messages,
@@ -1124,7 +1124,7 @@ export const Commands = [
         description: _td("Sends the given emote coloured as a rainbow"),
         args: '<message>',
         runFn: function(roomId, args) {
-            if (!args) return reject(this.getUserId());
+            if (!args) return reject(this.getUsage());
             return successSync(ContentHelpers.makeHtmlEmote(args, textToHtmlRainbow(args)));
         },
         category: CommandCategories.messages,
@@ -1207,7 +1207,7 @@ export const Commands = [
 
             return success((async () => {
                 if (isPhoneNumber) {
-                    const results = await LegacyCallHandler.instance.pstnLookup(this.state.value);
+                    const results = await LegacyCallHandler.instance.pstnLookup(userId);
                     if (!results || results.length === 0 || !results[0].userid) {
                         throw newTranslatableError("Unable to find Matrix ID for phone number");
                     }

src/autocomplete/QueryMatcher.ts

@@ -45,7 +45,7 @@ interface IOptions<T extends {}> {
  * @param {function[]} options.funcs List of functions that when called with the
  *     object as an arg will return a string to use as an index
  */
-export default class QueryMatcher<T extends Object> {
+export default class QueryMatcher<T extends {}> {
     private _options: IOptions<T>;
     private _items: Map<string, {object: T, keyWeight: number}[]>;
 

src/components/views/elements/Draggable.tsx

@@ -47,7 +47,7 @@ export default class Draggable extends React.Component<IProps, IState> {
         };
     }
 
-    private onMouseDown = (event: MouseEvent): void => {
+    private onMouseDown = (event: React.MouseEvent): void => {
         this.setState({
             location: {
                 currentX: event.clientX,
@@ -74,6 +74,6 @@ export default class Draggable extends React.Component<IProps, IState> {
     }
 
     render() {
-        return <div className={this.props.className} onMouseDown={this.onMouseDown.bind(this)} />;
+        return <div className={this.props.className} onMouseDown={this.onMouseDown} />;
     }
 }

src/components/views/elements/IRCTimelineProfileResizer.tsx

@@ -48,7 +48,7 @@ export default class IRCTimelineProfileResizer extends React.Component<IProps, I
         }, () => this.updateCSSWidth(this.state.width));
     }
 
-    private dragFunc = (location: ILocationState, event: React.MouseEvent<Element, MouseEvent>): ILocationState => {
+    private dragFunc = (location: ILocationState, event: MouseEvent): ILocationState => {
         const offset = event.clientX - location.currentX;
         const newWidth = this.state.width + offset;
 
@@ -77,7 +77,7 @@ export default class IRCTimelineProfileResizer extends React.Component<IProps, I
         this.state.IRCLayoutRoot.style.setProperty("--name-width", newWidth + "px");
     }
 
-    private onMoueUp(event: MouseEvent) {
+    private onMoueUp = () => {
         if (this.props.roomId) {
             SettingsStore.setValue(
                 "ircDisplayNameWidth",
@@ -86,13 +86,13 @@ export default class IRCTimelineProfileResizer extends React.Component<IProps, I
                 this.state.width,
             );
         }
-    }
+    };
 
     render() {
         return <Draggable
             className="mx_ProfileResizer"
-            dragFunc={this.dragFunc.bind(this)}
-            onMouseUp={this.onMoueUp.bind(this)}
+            dragFunc={this.dragFunc}
+            onMouseUp={this.onMoueUp}
         />;
     }
 }

src/components/views/elements/Validation.tsx

@@ -15,7 +15,6 @@ See the License for the specific language governing permissions and
 limitations under the License.
 */
 
-/* eslint-disable @typescript-eslint/no-invalid-this */
 import React from "react";
 import classNames from "classnames";
 
@@ -46,7 +45,7 @@ interface IArgs<T, D = void> {
 export interface IFieldState {
     value: string;
     focused: boolean;
-    allowEmpty: boolean;
+    allowEmpty?: boolean;
 }
 
 export interface IValidationResult {
@@ -80,10 +79,13 @@ export interface IValidationResult {
  *     A validation function that takes in the current input value and returns
  *     the overall validity and a feedback UI that can be rendered for more detail.
  */
-export default function withValidation<T = undefined, D = void>({
+export default function withValidation<T = void, D = void>({
     description, hideDescriptionIfValid, deriveData, rules,
 }: IArgs<T, D>) {
-    return async function onValidate({ value, focused, allowEmpty = true }: IFieldState): Promise<IValidationResult> {
+    return async function onValidate(
+        this: T,
+        { value, focused, allowEmpty = true }: IFieldState,
+    ): Promise<IValidationResult> {
         if (!value && allowEmpty) {
             return {
                 valid: null,
@@ -96,7 +98,7 @@ export default function withValidation<T = undefined, D = void>({
 
         const results: IResult[] = [];
         let valid = true;
-        if (rules && rules.length) {
+        if (rules?.length) {
             for (const rule of rules) {
                 if (!rule.key || !rule.test) {
                     continue;

src/utils/Image.ts

@@ -31,7 +31,7 @@ function arrayBufferReadInt(arr: ArrayBuffer, start: number): number {
 }
 
 function arrayBufferReadStr(arr: ArrayBuffer, start: number, len: number): string {
-    return String.fromCharCode.apply(null, arrayBufferRead(arr, start, len));
+    return String.fromCharCode.apply(null, Array.from(arrayBufferRead(arr, start, len)));
 }
 
 export async function blobIsAnimated(mimeType: string | undefined, blob: Blob): Promise<boolean> {

src/utils/MegolmExportEncryption.ts

@@ -356,7 +356,7 @@ function packMegolmKeyFile(data: Uint8Array): ArrayBuffer {
 function encodeBase64(uint8Array: Uint8Array): string {
     // Misinterpt the Uint8Array as Latin-1.
     // window.btoa expects a unicode string with codepoints in the range 0-255.
-    const latin1String = String.fromCharCode.apply(null, uint8Array);
+    const latin1String = String.fromCharCode.apply(null, Array.from(uint8Array));
     // Use the builtin base64 encoder.
     return window.btoa(latin1String);
 }

test/ContentMessages-test.ts

@@ -131,9 +131,9 @@ describe("ContentMessages", () => {
             jest.spyOn(document, "createElement").mockImplementation(tagName => {
                 const element = createElement(tagName);
                 if (tagName === "video") {
-                    element.load = jest.fn();
-                    element.play = () => element.onloadeddata(new Event("loadeddata"));
-                    element.pause = jest.fn();
+                    (<HTMLVideoElement>element).load = jest.fn();
+                    (<HTMLVideoElement>element).play = () => element.onloadeddata(new Event("loadeddata"));
+                    (<HTMLVideoElement>element).pause = jest.fn();
                     Object.defineProperty(element, 'videoHeight', {
                         get() { return 600; },
                     });

test/Notifier-test.ts

@@ -433,4 +433,11 @@ describe("Notifier", () => {
             expect(Notifier._displayPopupNotification).toHaveBeenCalledTimes(1);
         });
     });
+
+    describe("setPromptHidden", () => {
+        it("should persist by default", () => {
+            Notifier.setPromptHidden(true);
+            expect(localStorage.getItem("notifications_hidden")).toBeTruthy();
+        });
+    });
 });

test/SlashCommands-test.tsx

@@ -225,4 +225,19 @@ describe('SlashCommands', () => {
             expect(client.leaveRoomChain).toHaveBeenCalledWith("room-id", expect.anything());
         });
     });
+
+    describe.each([
+        "rainbow",
+        "rainbowme",
+    ])("/%s", (commandName: string) => {
+        const command = findCommand(commandName);
+
+        it("should return usage if no args", () => {
+            expect(command.run(roomId, null, null).error).toBe(command.getUsage());
+        });
+
+        it("should make things rainbowy", () => {
+            return expect(command.run(roomId, null, "this is a test message").promise).resolves.toMatchSnapshot();
+        });
+    });
 });

test/__snapshots__/SlashCommands-test.tsx.snap

@@ -0,0 +1,19 @@
+// Jest Snapshot v1, https://goo.gl/fbAQLP
+
+exports[`SlashCommands /rainbow should make things rainbowy 1`] = `
+{
+  "body": "this is a test message",
+  "format": "org.matrix.custom.html",
+  "formatted_body": "<font color="#ff00be">t</font><font color="#ff0080">h</font><font color="#ff0041">i</font><font color="#ff5f00">s</font> <font color="#faa900">i</font><font color="#c3bf00">s</font> <font color="#00d800">a</font> <font color="#00e371">t</font><font color="#00e6b6">e</font><font color="#00e7f8">s</font><font color="#00e7ff">t</font> <font color="#00deff">m</font><font color="#00d2ff">e</font><font color="#00c0ff">s</font><font color="#44a4ff">s</font><font color="#e87dff">a</font><font color="#ff42ff">g</font><font color="#ff00fe">e</font>",
+  "msgtype": "m.text",
+}
+`;
+
+exports[`SlashCommands /rainbowme should make things rainbowy 1`] = `
+{
+  "body": "this is a test message",
+  "format": "org.matrix.custom.html",
+  "formatted_body": "<font color="#ff00be">t</font><font color="#ff0080">h</font><font color="#ff0041">i</font><font color="#ff5f00">s</font> <font color="#faa900">i</font><font color="#c3bf00">s</font> <font color="#00d800">a</font> <font color="#00e371">t</font><font color="#00e6b6">e</font><font color="#00e7f8">s</font><font color="#00e7ff">t</font> <font color="#00deff">m</font><font color="#00d2ff">e</font><font color="#00c0ff">s</font><font color="#44a4ff">s</font><font color="#e87dff">a</font><font color="#ff42ff">g</font><font color="#ff00fe">e</font>",
+  "msgtype": "m.emote",
+}
+`;

test/components/views/Validation-test.ts

@@ -0,0 +1,31 @@
+/*
+Copyright 2022 The Matrix.org Foundation C.I.C.
+
+Licensed under the Apache License, Version 2.0 (the "License");
+you may not use this file except in compliance with the License.
+You may obtain a copy of the License at
+
+    http://www.apache.org/licenses/LICENSE-2.0
+
+Unless required by applicable law or agreed to in writing, software
+distributed under the License is distributed on an "AS IS" BASIS,
+WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+See the License for the specific language governing permissions and
+limitations under the License.
+*/
+
+import withValidation from "../../../src/components/views/elements/Validation";
+
+describe("Validation", () => {
+    it("should handle 0 rules", () => {
+        const handler = withValidation({
+            rules: [],
+        });
+        return expect(handler({
+            value: "value",
+            focused: true,
+        })).resolves.toEqual(expect.objectContaining({
+            valid: true,
+        }));
+    });
+});

test/test-utils/audio.ts

@@ -46,20 +46,20 @@ export const createTestPlayback = (): Playback => {
             return true;
         },
         // EventEmitter
-        on: eventEmitter.on.bind(eventEmitter),
-        once: eventEmitter.once.bind(eventEmitter),
-        off: eventEmitter.off.bind(eventEmitter),
-        addListener: eventEmitter.addListener.bind(eventEmitter),
-        removeListener: eventEmitter.removeListener.bind(eventEmitter),
-        removeAllListeners: eventEmitter.removeAllListeners.bind(eventEmitter),
-        getMaxListeners: eventEmitter.getMaxListeners.bind(eventEmitter),
-        setMaxListeners: eventEmitter.setMaxListeners.bind(eventEmitter),
-        listeners: eventEmitter.listeners.bind(eventEmitter),
-        rawListeners: eventEmitter.rawListeners.bind(eventEmitter),
-        listenerCount: eventEmitter.listenerCount.bind(eventEmitter),
-        eventNames: eventEmitter.eventNames.bind(eventEmitter),
-        prependListener: eventEmitter.prependListener.bind(eventEmitter),
-        prependOnceListener: eventEmitter.prependOnceListener.bind(eventEmitter),
+        on: eventEmitter.on.bind(eventEmitter) as Playback["on"],
+        once: eventEmitter.once.bind(eventEmitter) as Playback["once"],
+        off: eventEmitter.off.bind(eventEmitter) as Playback["off"],
+        addListener: eventEmitter.addListener.bind(eventEmitter) as Playback["addListener"],
+        removeListener: eventEmitter.removeListener.bind(eventEmitter) as Playback["removeListener"],
+        removeAllListeners: eventEmitter.removeAllListeners.bind(eventEmitter) as Playback["removeAllListeners"],
+        getMaxListeners: eventEmitter.getMaxListeners.bind(eventEmitter) as Playback["getMaxListeners"],
+        setMaxListeners: eventEmitter.setMaxListeners.bind(eventEmitter) as Playback["setMaxListeners"],
+        listeners: eventEmitter.listeners.bind(eventEmitter) as Playback["listeners"],
+        rawListeners: eventEmitter.rawListeners.bind(eventEmitter) as Playback["rawListeners"],
+        listenerCount: eventEmitter.listenerCount.bind(eventEmitter) as Playback["listenerCount"],
+        eventNames: eventEmitter.eventNames.bind(eventEmitter) as Playback["eventNames"],
+        prependListener: eventEmitter.prependListener.bind(eventEmitter) as Playback["prependListener"],
+        prependOnceListener: eventEmitter.prependOnceListener.bind(eventEmitter) as Playback["prependOnceListener"],
         liveData: new SimpleObservable<number[]>(),
         durationSeconds: 31415,
         timeSeconds: 3141,

tsconfig.json

@@ -17,7 +17,10 @@
       "es2020",
       "dom",
       "dom.iterable"
-    ]
+    ],
+    "alwaysStrict": true,
+    "strictBindCallApply": true,
+    "noImplicitThis": true
   },
   "include": [
     "./src/**/*.ts",

yarn.lock

@@ -9451,10 +9451,10 @@ typedarray-to-buffer@^3.1.5:
   dependencies:
     is-typedarray "^1.0.0"
 
-typescript@4.7.4:
-  version "4.7.4"
-  resolved "https://registry.yarnpkg.com/typescript/-/typescript-4.7.4.tgz#1a88596d1cf47d59507a1bcdfb5b9dfe4d488235"
-  integrity sha512-C0WQT0gezHuw6AdY1M2jxUO83Rjf0HP7Sk1DtXj6j1EwkQNZrHAg2XPWlq62oqEhYvONq5pkC2Y9oPljWToLmQ==
+typescript@4.8.4:
+  version "4.8.4"
+  resolved "https://registry.yarnpkg.com/typescript/-/typescript-4.8.4.tgz#c464abca159669597be5f96b8943500b238e60e6"
+  integrity sha512-QCh+85mCy+h0IGff8r5XWzOVSbBO+KfeYrMQh7NJ58QujwcE22u+NUSmUxqF+un70P9GXKxa2HCNiTTMJknyjQ==
 
 ua-parser-js@^0.7.30:
   version "0.7.31"