Setting Up a Controlled Component

Prologue A while ago, I decided to develop a fully accessible main navigation component in React and write a series of articles documenting the steps it took to create a non-trivial accessible component. In my last development article , I finally completed the requirements for delivering an uncontrolled navigation component with a horizontal layout; with full keyboard functionality, along with adding the niceties of closing sublists when lists are closed and making sure any open sublist on the top row closes when focus shifts away from it. Rather than write an entirely new component for a mobile version, I'm going to modify the existing code. This first article outlines the steps necessary to set up and work with a controlled component. -— Note : This article is one of a series demonstrating building a React navigational component from scratch while considering accessibility through the process. The articles are accompanied by a GitHub repository with releases tied to one or more articles; each builds on the previous one until a fully implemented navigation component is complete. Each release and its associated tag contain fully runnable code for the article. The code discussed in this article is available in the release. and may be downloaded at release 1.0.0 . Links in the article will take you to the proper file in the tagged GitHub Repository. Because the code for this release is scattered across components, line numbers are added to make it easier to locate in the linked GitHub file. Line numbers are also provided for those who would like to follow along with a downloaded copy. While code examples are written in JavaScript for brevity, all actual code is written in Typescript and targets React 19.x, all while using vanilla CSS. Examples use Next.js v16.x, which is not required to run the navigation component. You can view the requirements for the Controlled Components Release along with previous requirements. Content Links Introduction Acceptance Criteria Contr