diff --git a/src/leaf/map/fullscreen/state/use-boolean.ts b/src/leaf/map/fullscreen/state/use-boolean.ts
new file mode 100644
index 0000000..02eebfa
--- /dev/null
+++ b/src/leaf/map/fullscreen/state/use-boolean.ts
@@ -0,0 +1,16 @@
+export type UseBoolean = {
+  get: () => boolean
+  toggle: () => void
+}
+
+export function useBoolean(initialValue: boolean): UseBoolean {
+  let state: boolean = initialValue
+  return {
+    get(): boolean {
+      return state
+    },
+    toggle(): void {
+      state = !state
+    },
+  }
+}
diff --git a/src/leaf/map/fullscreen/state/use-link.ts b/src/leaf/map/fullscreen/state/use-link.ts
new file mode 100644
index 0000000..b3aa704
--- /dev/null
+++ b/src/leaf/map/fullscreen/state/use-link.ts
@@ -0,0 +1,34 @@
+import { DomEvent } from 'leaflet'
+
+export type UseLinkOptions = {
+  element: HTMLAnchorElement
+  initialProps: Record<string, string>
+}
+
+export type UseLink = {
+  onClick: (handler: (event: Event) => Promise<void>) => void
+  assign: (props: Record<string, string>) => HTMLAnchorElement
+}
+
+const domEventOn = <
+  (
+    el: HTMLElement,
+    types: string,
+    fn: (event: Event) => Promise<void>,
+  ) => typeof DomEvent
+>DomEvent.on
+
+export function useLink({ element, initialProps }: UseLinkOptions): UseLink {
+  function assign(props: Record<string, string>): HTMLAnchorElement {
+    return Object.assign(element, props)
+  }
+
+  assign(initialProps)
+
+  return {
+    assign,
+    onClick(handler: (event: Event) => Promise<void>): void {
+      domEventOn(element, 'click', handler)
+    },
+  }
+}