Also see https://www.twilio.com/blog/audio-visualisation-web-audio-api--react
This is an example application that shows how to visualise audio from the microphone using the Web Audio API in React.
You need Node.js installed to run the application.
Clone or download the project from GitHub, change into the directory and install the dependencies.
git clone https://github.com/philnash/react-web-audio.git
cd react-web-audio
npm install
Start the application:
npm start
And open the browser to http://localhost:3000/.
You're ready to built the rest of the application now.