Diffing refers to which process?

Diffing refers to which process?

• A. Updating the browser's fonts.
• B. Comparing the new virtual DOM with a previous version to figure out changes.
• C. Converting JSX to HTML.
• D. Compiling JavaScript to bytecode.

Answer: (B)

Diffing is the reconciliation step where React compares the new UI representation with what was rendered before. When the state or props change, React builds a fresh virtual DOM tree and then walks both the new and previous trees to identify exactly what has changed. This allows React to produce the minimal set of updates needed for the real DOM, keeping the UI in sync while avoiding unnecessary edits. Think of the virtual DOM as a lightweight in-memory model of the UI. The diffing process finds the differences between the new model and the old one and translates those differences into precise DOM operations (like insert, update, or delete). This is what makes updates fast and efficient. Other options describe different tasks: converting JSX to HTML is a compile-time step, not a runtime diffing process; updating fonts is a styling task unrelated to reconciling UI changes; and compiling JavaScript to bytecode is a language-implementation detail, not about diffing the UI.

Diffing is the reconciliation step where React compares the new UI representation with what was rendered before. When the state or props change, React builds a fresh virtual DOM tree and then walks both the new and previous trees to identify exactly what has changed. This allows React to produce the minimal set of updates needed for the real DOM, keeping the UI in sync while avoiding unnecessary edits.

Think of the virtual DOM as a lightweight in-memory model of the UI. The diffing process finds the differences between the new model and the old one and translates those differences into precise DOM operations (like insert, update, or delete). This is what makes updates fast and efficient.

Other options describe different tasks: converting JSX to HTML is a compile-time step, not a runtime diffing process; updating fonts is a styling task unrelated to reconciling UI changes; and compiling JavaScript to bytecode is a language-implementation detail, not about diffing the UI.