Interactive Comments with React + CSS [Question]

Hi everybody! Currently working on the interactive comments challenge, unfortunately I got kind of stuck nearing completion. I'm hoping someone can help with this.

The question: I can't seem to figure out how to update the replies array in the data (or comments array), for 'posting' a new reply to a comment. So essentially my question boils down to: how to update a specific array with a new object, which is nested within the main comments array? (within the repo see the data.js file for the data and the context.jsx for all functions handling the data)

Thanks! And have a nice weekend :)