Memoization Techniques

Press the Add button on one row of a three-row catalog, and this appears in the console.

Filtering
Rendering Kettle
Rendering Toaster
Rendering Blender

One number changed on the screen, the count of items in the cart. Even so, the app filtered the whole list again and rendered all three rows again. With three rows you would never notice, but with a filter over thousands of products and rows that hold images, this repeated work is what makes a screen feel slow.

Here is the screen that produced that log