Panning and zooming are popular interaction techniques which let the user focus on a region of interest by restricting the view.

The zoom behavior implemented by d3-zoom is a convenient but flexible abstraction for enabling pan-and-zoom on selections. It handles a surprising variety of input events and browser quirks. The zoom behavior is agnostic about the DOM, so you can use it with SVG, HTML or Canvas.

Node.js is an event-based server-side JavaScript engine.