Complete refactor (#123)

src/app/components/Dropdown.ts

@@ -0,0 +1,22 @@
+import { Property } from '../state/Property';
+import { View } from '../views/View';
+import { Octicon } from './Octicon';
+
+export const Dropdown = (view: View, icon: keyof typeof Octicon, entries: [string, string][], state: Property<string>, watcher?: (value: string) => void) => {
+  const dropdown = view.register(el => {
+    el.addEventListener('change', () => {
+      state.set((el as HTMLSelectElement).value)
+    })
+    state.watchRun(v => (el as HTMLSelectElement).value = v, 'dropdown')
+    watcher?.(state.get())
+  })
+  return `
+  <div class="dropdown">
+    <select data-id="${dropdown}">
+      ${entries.map(e => `
+        <option value=${e[0]}>${e[1]}</option>
+      `).join('')}
+    </select>
+    ${Octicon[icon]}
+  </div>`
+}