A blank slate starting point showing the "Hello World" for the VizHub V3 Runtime Environment, which supports continuous hot reloading with interactive widgets.

• There is no index.html - that's what triggers the V3 Runtime
• The entry point is the main function exported from index.js
• The main function takes an argument container, a DIV that has measurable dimensions using clientWidth and clientHeight
• The second argument to main is an options object containing state and setState.
• The state of the application is stored in state, which is initialized as an empty object {}.
• The setState function can be called with a function that uses the previous state to create a new state object using immutable update patterns.
• For an interactive example, see Mouse Follower.

Full course playlist: YouTube: Constructing Visualization 2024.