增加了提issue的功能

Signed-off-by: Chen Xiao <abigwc@gmail.com>

client/node_modules/date-fns/isExists.js

@@ -0,0 +1,35 @@
+/**
+ * @name isExists
+ * @category Common Helpers
+ * @summary Is the given date exists?
+ *
+ * @description
+ * Checks if the given arguments convert to an existing date.
+ *
+ * @param year - The year of the date to check
+ * @param month - The month of the date to check
+ * @param day - The day of the date to check
+ *
+ * @returns `true` if the date exists
+ *
+ * @example
+ * // For the valid date:
+ * const result = isExists(2018, 0, 31)
+ * //=> true
+ *
+ * @example
+ * // For the invalid date:
+ * const result = isExists(2018, 1, 31)
+ * //=> false
+ */
+export function isExists(year, month, day) {
+  const date = new Date(year, month, day);
+  return (
+    date.getFullYear() === year &&
+    date.getMonth() === month &&
+    date.getDate() === day
+  );
+}
+
+// Fallback for modularized imports:
+export default isExists;