refactor(client): fix TypeScript errors from MkPageHeader

[saschanaz]

What

MkPageHeaderの様々なTypeScriptエラーを修正 / Fixed several TypeScript errors from MkPageHeader

Why

エラーの数を減らすため / To reduce errors

Additional info (optional)

[codecov]

Codecov Report

Merging #9400 (dd1b131) into develop (c0fc0b9) will not change coverage.
The diff coverage is n/a.

@@           Coverage Diff            @@
##           develop    #9400   +/-   ##
========================================
  Coverage    22.41%   22.41%           
========================================
  Files          702      702           
  Lines        65785    65785           
  Branches      2127     2127           
========================================
  Hits         14748    14748           
  Misses       51037    51037           

Help us with your feedback. Take ten seconds to tell us how you rate us. Have a feature suggestion? Share it here.

[syuilo]

why?

[tamaina]

TypeScript様がいうにはev.targetはEventTarget | null

EventTarget↓

/** EventTarget is a DOM interface implemented by objects that can receive events and may have listeners for them. */
interface EventTarget {
    /**
     * Appends an event listener for events whose type attribute value is type. The callback argument sets the callback that will be invoked when the event is dispatched.
     *
     * The options argument sets listener-specific options. For compatibility this can be a boolean, in which case the method behaves exactly as if the value was specified as options's capture.
     *
     * When set to true, options's capture prevents callback from being invoked when the event's eventPhase attribute value is BUBBLING_PHASE. When false (or not present), callback will not be invoked when event's eventPhase attribute value is CAPTURING_PHASE. Either way, callback will be invoked if event's eventPhase attribute value is AT_TARGET.
     *
     * When set to true, options's passive indicates that the callback will not cancel the event by invoking preventDefault(). This is used to enable performance optimizations described in § 2.8 Observing event listeners.
     *
     * When set to true, options's once indicates that the callback will only be invoked once after which the event listener will be removed.
     *
     * If an AbortSignal is passed for options's signal, then the event listener will be removed when signal is aborted.
     *
     * The event listener is appended to target's event listener list and is not appended if it has the same type, callback, and capture.
     */
    addEventListener(type: string, callback: EventListenerOrEventListenerObject | null, options?: AddEventListenerOptions | boolean): void;
    /** Dispatches a synthetic event event to target and returns true if either event's cancelable attribute value is false or its preventDefault() method was not invoked, and false otherwise. */
    dispatchEvent(event: Event): boolean;
    /** Removes the event listener in target's event listener list with the same type, callback, and options. */
    removeEventListener(type: string, callback: EventListenerOrEventListenerObject | null, options?: EventListenerOptions | boolean): void;
}

[syuilo]

ev.currentTarget ?? ev.targetをev.currentTargetにしたら挙動変わってしまわない？

[tamaina]

わかる

直した

[saschanaz]

event listenerですからcurrentTargetは常にnullじゃなくEventTargetになるのでokです

(event listenerのそとでしたらちがう話になりますが)

[saschanaz]

その説明をしておくべきでした、すみません😵‍💫