React
Typescript
React Page Editor was made because existing solutions for drag-and-drop page editors were limited at the time.
The desire was for an editor that was intuitive to use, could use components supplied by the developer, be able to change typed component props within the UI, and return a JSON object that could then be used to render the page. This JSON object could be saved in a database, so the editor could be used as a frontend for a website CMS for instance.
Existing solutions at the time were limited in what components could be used, how flexible they were for editing those components, or only outputted raw HTML.