Resolve "Increment/decrement value in NumberInput when +/- button is kept pushed."

src/utils/hooks.js

@@ -0,0 +1,20 @@
+/*
+ * Copyright (C) 2019 CZ.NIC z.s.p.o. (http://www.nic.cz/)
+ *
+ * This is free software, licensed under the GNU General Public License v3.
+ * See /LICENSE for more information.
+ */
+
+import { useState, useEffect } from "react";
+
+/** Execute callback when condition is set to true. */
+export function useConditionalTimeout({ callback, timeout = 125 }, ...callbackArgs) {
+    const [condition, setCondition] = useState(false);
+    useEffect(() => {
+        if (condition) {
+            const interval = setTimeout(() => callback(...callbackArgs), timeout);
+            return () => setTimeout(interval);
+        }
+    }, [condition, callback, timeout, callbackArgs]);
+    return setCondition;
+}