Ace the Angular Interview 2025 – Code Your Way to Success!

Using ngFor with a track by function primarily offers the advantage of reducing the rendering time for complex lists. When Angular renders lists, it will track which items have changed, been added, or removed. By implementing a track by function, developers can optimize this tracking process.

The track by function helps Angular identify individual items in the list based on a unique identifier (like an ID), rather than relying on the default behavior, which involves checking the entire object for any changes. This is especially beneficial for large lists, where the performance impact can be significant. When items in the list change, Angular can reuse existing elements in the DOM instead of recreating them, which minimizes performance overhead caused by unnecessary re-rendering.

In complex lists where data updates frequently or items are dynamically added or removed, leveraging a track by function leads to a more efficient rendering process, ultimately providing a smoother user experience.