I’ve been porting some previously server-rendered Rails templates to instead sit within a React application. This particular application uses Foundation Sites for base styles, and uses some of Foundation’s components which use Javascript to function - mostly basic stuff like data-dropdown, data-accordion, data-tabs. Foundation (still) uses jQuery for setting up these elements, and by default, initializes based on the ready event. This is at odds with React, since components are dynamically added and removed from the DOM.

To get this working, I first moved the markup that was in a template into a functional component:

// app/frontend/components/Dropdown.jsx
import React from "react";

export default () => (
    <button class="button" type="button" data-toggle="example-dropdown">Toggle Dropdown</button>
    <div class="dropdown-pane" id="example-dropdown" data-dropdown data-auto-focus="true">
      Example dropdown.


The component renders, but the dropdown doesn’t work! This is because the component has been mounted to the page after Foundation has initialised.

To resolve this, I used two React hooks useRef and useEffect. useRef is used to establish a reference to the DOM node, and useEffect is used to run a function when the component has rendered.

Here’s how the hooks are used in the working component:

// app/frontend/components/Dropdown.jsx
import React, { useRef, useEffect } from "react";
import jQuery from "jquery";
import "foundation-sites";

export default () => {
  const foundationRef = useRef(null);
  useEffect(() => jQuery(foundationRef.current).foundation(), [foundationRef]);

  return (
    <div ref={foundationRef}>
      <button class="button" type="button" data-toggle="example-dropdown">
        Toggle Dropdown
        Example dropdown.


The first argument to useRef is set to null, as there is no additional value to use until the component is mounted. useEffect accepts the ref as a dependency, as it only needs to render when the ref changes (e.g. when the component is mounted), not every re-render.

Foundation JS is getting pretty dated these days - it’s a heavy dependency, and still relies on jQuery to work correctly. For projects already using the framework though, it provides a useful mixture of styles and scripts, so it’s worthwhile being able to continue to leverage these javascript-backed behaviours in React components.