The left panel is imperative JavaScript that formats a currency input field. It queries the DOM for the element, attaches an event listener, parses the input string, strips non-numeric characters, handles edge cases for decimal precision, formats with locale-aware thousands separators, updates the DOM, positions the cursor, and manages focus/blur states. Seventy-three lines of instructions that tell the browser exactly how to accomplish the formatting, step by step.
The right panel is the same behavior expressed as HTML attributes. The genX library reads six attributes from the element, infers the intended behavior, and generates the same formatting logic internally. The developer declared what the input should do. The platform decided how.
The declarative version is not shorter because it does less. It is shorter because the developer specified the outcome and the platform handled the implementation. The 73 lines of imperative code still exist; they run inside genX, tested once, correct everywhere. The developer's surface area shrank from 73 lines to 6 attributes. Fewer lines means fewer bugs, because every line you write is a line that can be wrong.