D3.js`, a popular data visualization library, can struggle with rendering large datasets on a single thread, leading to "jank" or unresponsiveness. To address this issue, the author of the blog post delves into D3's internals and develops a custom batched rendering approach to optimize performance. By breaking down the rendering process into smaller chunks and using timeouts to manage the execution order, the author creates a responsive visual profiler that can handle large datasets without freezing the browser. The solution involves modifying D3's selections to work with batches of data, rather than relying on the library's native functionality.