初始化项目

packages/hooks/src/use-count-down.ts

@@ -0,0 +1,49 @@
+import { computed, onScopeDispose, ref } from 'vue';
+import { useRafFn } from '@vueuse/core';
+
+/**
+ * count down
+ *
+ * @param seconds - count down seconds
+ */
+export default function useCountDown(seconds: number) {
+  const FPS_PER_SECOND = 60;
+
+  const fps = ref(0);
+
+  const count = computed(() => Math.ceil(fps.value / FPS_PER_SECOND));
+
+  const isCounting = computed(() => fps.value > 0);
+
+  const { pause, resume } = useRafFn(
+    () => {
+      if (fps.value > 0) {
+        fps.value -= 1;
+      } else {
+        pause();
+      }
+    },
+    { immediate: false }
+  );
+
+  function start(updateSeconds: number = seconds) {
+    fps.value = FPS_PER_SECOND * updateSeconds;
+    resume();
+  }
+
+  function stop() {
+    fps.value = 0;
+    pause();
+  }
+
+  onScopeDispose(() => {
+    pause();
+  });
+
+  return {
+    count,
+    isCounting,
+    start,
+    stop
+  };
+}