mermaid-js/mermaid ? reverse-engineered prompt

I want to create a web-based tool that makes it super easy for people to create diagrams and charts from text. The main idea is that someone could write simple, markdown-like text to define a flowchart, sequence diagram, or even a mind map, and the tool would render it as a clean-looking SVG diagram. This would be amazing for technical documentation, as the diagrams could be version-controlled right alongside the code.

It should be primarily a JavaScript library that can be embedded in any website, but I also want a "Live Editor" demo site. This site would have a split view where a user can type their diagram text on the left and see the visual diagram update in real-time on the right. Please build this using TypeScript for the core library. It needs to be robust and well-tested so it can be integrated into popular platforms like GitHub.