Create flexbox layout helper (#11411)

src/components/utils/Flex.tsx

@@ -0,0 +1,86 @@
+/*
+Copyright 2023 The Matrix.org Foundation C.I.C.
+
+Licensed under the Apache License, Version 2.0 (the "License");
+you may not use this file except in compliance with the License.
+You may obtain a copy of the License at
+
+    http://www.apache.org/licenses/LICENSE-2.0
+
+Unless required by applicable law or agreed to in writing, software
+distributed under the License is distributed on an "AS IS" BASIS,
+WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+See the License for the specific language governing permissions and
+limitations under the License.
+*/
+
+import classNames from "classnames";
+import React, { useEffect, useRef } from "react";
+
+type FlexProps = {
+    /**
+     * The type of the HTML element
+     * @default div
+     */
+    as?: string;
+    /**
+     * The CSS class name.
+     */
+    className?: string;
+    /**
+     * The type of flex container
+     * @default flex
+     */
+    display?: "flex" | "inline-flex";
+    /**
+     * The flow direction of the flex children
+     * @default row
+     */
+    direction?: "row" | "column" | "row-reverse" | "column-reverse";
+    /**
+     * The alingment of the flex children
+     * @default start
+     */
+    align?: "start" | "center" | "end" | "baseline" | "stretch";
+    /**
+     * The justification of the flex children
+     * @default start
+     */
+    justify?: "start" | "center" | "end" | "between";
+    /**
+     * The spacing between the flex children, expressed with the CSS unit
+     * @default 0
+     */
+    gap?: string;
+    /**
+     * the on click event callback
+     */
+    onClick?: (e: React.MouseEvent) => void;
+};
+
+/**
+ * A flexbox container helper
+ */
+export function Flex({
+    as = "div",
+    display = "flex",
+    direction = "row",
+    align = "start",
+    justify = "start",
+    gap = "0",
+    className,
+    children,
+    ...props
+}: React.PropsWithChildren<FlexProps>): JSX.Element {
+    const ref = useRef<HTMLElement>();
+
+    useEffect(() => {
+        ref.current!.style.setProperty(`--mx-flex-display`, display);
+        ref.current!.style.setProperty(`--mx-flex-direction`, direction);
+        ref.current!.style.setProperty(`--mx-flex-align`, align);
+        ref.current!.style.setProperty(`--mx-flex-justify`, justify);
+        ref.current!.style.setProperty(`--mx-flex-gap`, gap);
+    }, [align, direction, display, gap, justify]);
+
+    return React.createElement(as, { ...props, className: classNames("mx_Flex", className), ref }, children);
+}