Function registerPointerEvent

packages/melonjs/src/input/pointerevent.ts:710–752

(
	eventType: string,
	region: any,
	callback: (pointer: Pointer) => boolean | void,
)

 *  },
 */
export function registerPointerEvent(
	eventType: string,
	region: any,
	callback: (pointer: Pointer) => boolean | void,
): void {
	// make sure the mouse/touch events are initialized
	enablePointerEvent();

	if (pointerEventList.indexOf(eventType) === -1) {
		throw new Error(`invalid event type : ${eventType}`);
	}

	if (typeof region === "undefined") {
		throw new Error(
			`registerPointerEvent: region for ${String(region)} event is undefined `,
		);
	}

	const eventTypes = findAllActiveEvents(
		activeEventList,
		pointerEventMap[eventType],
	);

	// register the event
	if (!eventHandlers.has(region)) {
		eventHandlers.set(region, {
			region: region,
			callbacks: {},
			pointerId: null,
		});
	}

	// allocate array if not defined
	const handlers = eventHandlers.get(region)!;
	for (let i = 0; i < eventTypes.length; i++) {
		const eventType = eventTypes[i];
		if (handlers.callbacks[eventType]) {
			handlers.callbacks[eventType].push(callback);
		} else {
			handlers.callbacks[eventType] = [callback];
		}
	}
}

/**
 * allows the removal of event listeners from the object target.