Enable @typescript-eslint/explicit-function-return-type in /src (#9788)

* Enable `@typescript-eslint/explicit-member-accessibility` on /src

* Prettier

* Enable `@typescript-eslint/explicit-function-return-type` in /src

* Fix types

* tsc strict fixes

* Delint

* Fix test

* Fix bad merge

src/components/views/audio_messages/AudioPlayerBase.tsx

@@ -61,7 +61,7 @@ export default abstract class AudioPlayerBase<T extends IProps = IProps> extends
         });
     }
 
-    protected onKeyDown = (ev: React.KeyboardEvent) => {
+    protected onKeyDown = (ev: React.KeyboardEvent): void => {
         let handled = true;
         const action = getKeyBindingsManager().getAccessibilityAction(ev);
 
@@ -88,7 +88,7 @@ export default abstract class AudioPlayerBase<T extends IProps = IProps> extends
         }
     };
 
-    private onPlaybackUpdate = (ev: PlaybackState) => {
+    private onPlaybackUpdate = (ev: PlaybackState): void => {
         this.setState({ playbackPhase: ev });
     };
 

src/components/views/audio_messages/Clock.tsx

@@ -43,7 +43,7 @@ export default class Clock extends React.Component<Props> {
         return currentFloor !== nextFloor;
     }
 
-    public render() {
+    public render(): JSX.Element {
         return (
             <span aria-live={this.props["aria-live"]} role={this.props.role} className="mx_Clock">
                 {this.props.formatFn(this.props.seconds)}

src/components/views/audio_messages/DurationClock.tsx

@@ -44,11 +44,11 @@ export default class DurationClock extends React.PureComponent<IProps, IState> {
         this.props.playback.clockInfo.liveData.onUpdate(this.onTimeUpdate);
     }
 
-    private onTimeUpdate = (time: number[]) => {
+    private onTimeUpdate = (time: number[]): void => {
         this.setState({ durationSeconds: time[1] });
     };
 
-    public render() {
+    public render(): JSX.Element {
         return <Clock seconds={this.state.durationSeconds} />;
     }
 }

src/components/views/audio_messages/LiveRecordingClock.tsx

@@ -46,20 +46,20 @@ export default class LiveRecordingClock extends React.PureComponent<IProps, ISta
         };
     }
 
-    public componentDidMount() {
+    public componentDidMount(): void {
         this.props.recorder.liveData.onUpdate((update: IRecordingUpdate) => {
             this.seconds = update.timeSeconds;
             this.scheduledUpdate.mark();
         });
     }
 
-    private updateClock() {
+    private updateClock(): void {
         this.setState({
             seconds: this.seconds,
         });
     }
 
-    public render() {
+    public render(): JSX.Element {
         return <Clock seconds={this.state.seconds} aria-live="off" />;
     }
 }

src/components/views/audio_messages/LiveRecordingWaveform.tsx

@@ -51,7 +51,7 @@ export default class LiveRecordingWaveform extends React.PureComponent<IProps, I
         };
     }
 
-    public componentDidMount() {
+    public componentDidMount(): void {
         this.props.recorder.liveData.onUpdate((update: IRecordingUpdate) => {
             // The incoming data is between zero and one, so we don't need to clamp/rescale it.
             this.waveform = arrayFastResample(Array.from(update.waveform), RECORDING_PLAYBACK_SAMPLES);
@@ -59,11 +59,11 @@ export default class LiveRecordingWaveform extends React.PureComponent<IProps, I
         });
     }
 
-    private updateWaveform() {
+    private updateWaveform(): void {
         this.setState({ waveform: this.waveform });
     }
 
-    public render() {
+    public render(): JSX.Element {
         return <Waveform relHeights={this.state.waveform} />;
     }
 }

src/components/views/audio_messages/PlayPauseButton.tsx

@@ -39,12 +39,12 @@ export default class PlayPauseButton extends React.PureComponent<IProps> {
         super(props);
     }
 
-    private onClick = () => {
+    private onClick = (): void => {
         // noinspection JSIgnoredPromiseFromCall
         this.toggleState();
     };
 
-    public async toggleState() {
+    public async toggleState(): Promise<void> {
         await this.props.playback.toggle();
     }
 

src/components/views/audio_messages/PlaybackClock.tsx

@@ -55,17 +55,17 @@ export default class PlaybackClock extends React.PureComponent<IProps, IState> {
         this.props.playback.clockInfo.liveData.onUpdate(this.onTimeUpdate);
     }
 
-    private onPlaybackUpdate = (ev: PlaybackState) => {
+    private onPlaybackUpdate = (ev: PlaybackState): void => {
         // Convert Decoding -> Stopped because we don't care about the distinction here
         if (ev === PlaybackState.Decoding) ev = PlaybackState.Stopped;
         this.setState({ playbackPhase: ev });
     };
 
-    private onTimeUpdate = (time: number[]) => {
+    private onTimeUpdate = (time: number[]): void => {
         this.setState({ seconds: time[0], durationSeconds: time[1] });
     };
 
-    public render() {
+    public render(): JSX.Element {
         let seconds = this.state.seconds;
         if (this.state.playbackPhase === PlaybackState.Stopped) {
             if (Number.isFinite(this.props.defaultDisplaySeconds)) {

src/components/views/audio_messages/PlaybackWaveform.tsx

@@ -46,22 +46,22 @@ export default class PlaybackWaveform extends React.PureComponent<IProps, IState
         this.props.playback.clockInfo.liveData.onUpdate(this.onTimeUpdate);
     }
 
-    private toHeights(waveform: number[]) {
+    private toHeights(waveform: number[]): number[] {
         const seed = arraySeed(0, PLAYBACK_WAVEFORM_SAMPLES);
         return arrayTrimFill(waveform, PLAYBACK_WAVEFORM_SAMPLES, seed);
     }
 
-    private onWaveformUpdate = (waveform: number[]) => {
+    private onWaveformUpdate = (waveform: number[]): void => {
         this.setState({ heights: this.toHeights(waveform) });
     };
 
-    private onTimeUpdate = (time: number[]) => {
+    private onTimeUpdate = (time: number[]): void => {
         // Track percentages to a general precision to avoid over-waking the component.
         const progress = Number(percentageOf(time[0], 0, time[1]).toFixed(3));
         this.setState({ progress });
     };
 
-    public render() {
+    public render(): JSX.Element {
         return <Waveform relHeights={this.state.heights} progress={this.state.progress} />;
     }
 }

src/components/views/audio_messages/SeekBar.tsx

@@ -67,23 +67,23 @@ export default class SeekBar extends React.PureComponent<IProps, IState> {
         this.props.playback.liveData.onUpdate(() => this.animationFrameFn.mark());
     }
 
-    private doUpdate() {
+    private doUpdate(): void {
         this.setState({
             percentage: percentageOf(this.props.playback.timeSeconds, 0, this.props.playback.durationSeconds),
         });
     }
 
-    public left() {
+    public left(): void {
         // noinspection JSIgnoredPromiseFromCall
         this.props.playback.skipTo(this.props.playback.timeSeconds - ARROW_SKIP_SECONDS);
     }
 
-    public right() {
+    public right(): void {
         // noinspection JSIgnoredPromiseFromCall
         this.props.playback.skipTo(this.props.playback.timeSeconds + ARROW_SKIP_SECONDS);
     }
 
-    private onChange = (ev: ChangeEvent<HTMLInputElement>) => {
+    private onChange = (ev: ChangeEvent<HTMLInputElement>): void => {
         // Thankfully, onChange is only called when the user changes the value, not when we
         // change the value on the component. We can use this as a reliable "skip to X" function.
         //
@@ -91,7 +91,7 @@ export default class SeekBar extends React.PureComponent<IProps, IState> {
         this.props.playback.skipTo(Number(ev.target.value) * this.props.playback.durationSeconds);
     };
 
-    private onMouseDown = (event: React.MouseEvent<Element, MouseEvent>) => {
+    private onMouseDown = (event: React.MouseEvent<Element, MouseEvent>): void => {
         // do not propagate mouse down events, because these should be handled by the seekbar
         event.stopPropagation();
     };

src/components/views/audio_messages/Waveform.tsx

@@ -41,7 +41,7 @@ export default class Waveform extends React.PureComponent<IProps, IState> {
         progress: 1,
     };
 
-    public render() {
+    public render(): JSX.Element {
         return (
             <div className="mx_Waveform">
                 {this.props.relHeights.map((h, i) => {