feat: shortcuts auto repeating (#114)

Co-authored-by: Anthony Fu <anthonyfu117@hotmail.com>

Author: ecstrema

packages/client/logic/shortcuts.ts

@@ -1,23 +1,40 @@
-import { Fn, not, and, whenever } from '@vueuse/core'
+import { Fn, not, and } from '@vueuse/core'
+import { watch } from 'vue'
 import { fullscreen, magicKeys, shortcutsEnabled, isInputing, toggleOverview, showGotoDialog, showOverview, isOnFocus } from '../state'
 import { toggleDark } from './dark'
 import { next, nextSlide, prev, prevSlide } from './nav'
 
 const _shortcut = and(not(isInputing), not(isOnFocus), shortcutsEnabled)
 
-export function shortcut(key: string, fn: Fn) {
-  return whenever(and(magicKeys[key], _shortcut), fn, { flush: 'sync' })
+export function shortcut(key: string, fn: Fn, autoRepeat = false) {
+  const source = and(magicKeys[key], _shortcut)
+  let count = 0
+  let timer: any
+  const trigger = () => {
+    clearTimeout(timer)
+    if (!source.value) {
+      count = 0
+      return
+    }
+    if (autoRepeat) {
+      timer = setTimeout(trigger, Math.max(1000 - count * 250, 150))
+      count++
+    }
+    fn()
+  }
+
+  return watch(source, trigger, { flush: 'sync' })
 }
 
 export function registerShotcuts() {
   // global shortcuts
-  shortcut('space', next)
-  shortcut('right', next)
-  shortcut('left', prev)
-  shortcut('up', () => prevSlide(false))
-  shortcut('down', nextSlide)
-  shortcut('shift_left', () => prevSlide(false))
-  shortcut('shift_right', nextSlide)
+  shortcut('space', next, true)
+  shortcut('right', next, true)
+  shortcut('left', prev, true)
+  shortcut('up', () => prevSlide(false), true)
+  shortcut('down', nextSlide, true)
+  shortcut('shift_left', () => prevSlide(false), true)
+  shortcut('shift_right', nextSlide, true)
   shortcut('d', toggleDark)
   shortcut('f', () => fullscreen.toggle())
   shortcut('o', toggleOverview)