In this episode, we're focusing on hydrating the initial state from our controller and passing it down to the scroller component, so the correct checkboxes are checked when the page loads.
We'll start by making sure the current state and count values are handed off to the scroller component as plain props. Then, inside the scroller, we use defineProps to accept the state (a string) and the count (a number), and quickly confirm they're coming through correctly by dumping them to the page.
Next, we introduce the bitset JavaScript package to help us manage a potentially huge bit array efficiently—think of millions of checkboxes! We show how to install and import bitset, then demonstrate some basic usage, like setting and getting bits, and explain how this mirrors what happens in Redis.
The bulk of the work involves looping through the state string, converting each character to a number (0 or 1), and setting that in our bitset array. This step ensures each bit value represents whether a checkbox should be checked or not. After plugging this logic in, we double-check the memory usage and reassure you that handling even a massive bitset is okay for our use case.
Finally, when rendering the checkboxes, we use the bitset to determine which should be checked on initial render. We verify everything works, including for that 1 millionth checkbox if you were adventurous in the last episode!
At the end of this episode, you'll have learned how to take an initial state from your backend and hydrate your checkboxes (or whatever you're tracking) efficiently using a bitset, and you'll see how everything stays correct even with a huge amount of data.