Move contexts in a context folder

src/context/alertContext/AlertContext.js

@@ -0,0 +1,55 @@
+/*
+ * 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 React, { useState, useContext, useCallback } from "react";
+import PropTypes from "prop-types";
+
+import { Alert, ALERT_TYPES } from "../../bootstrap/Alert";
+import { Portal } from "../../utils/Portal";
+
+AlertContextProvider.propTypes = {
+    children: PropTypes.oneOfType([
+        PropTypes.arrayOf(PropTypes.node),
+        PropTypes.node,
+    ]),
+};
+
+function AlertContextProvider({ children }) {
+    const { AlertContext } = window;
+    const [alert, setAlert] = useState(null);
+
+    const setAlertWrapper = useCallback(
+        (message, type = ALERT_TYPES.DANGER) => {
+            setAlert({ message, type });
+        },
+        [setAlert]
+    );
+
+    const dismissAlert = useCallback(() => setAlert(null), [setAlert]);
+
+    return (
+        <>
+            {alert && (
+                <Portal containerId="alert-container">
+                    <Alert type={alert.type} onDismiss={dismissAlert}>
+                        {alert.message}
+                    </Alert>
+                </Portal>
+            )}
+            <AlertContext.Provider value={[setAlertWrapper, dismissAlert]}>
+                {children}
+            </AlertContext.Provider>
+        </>
+    );
+}
+
+function useAlert() {
+    const { AlertContext } = window;
+    return useContext(AlertContext);
+}
+
+export { AlertContextProvider, useAlert };