In Svelte, a derived store is a store whose value is calculated based on one or more other stores. Whenever the dependent stores change, the derived store automatically updates. This allows you to create reactive data transformations without manually subscribing to multiple stores.
You use Svelte's derived function to create a derived store. It takes the source store(s) and a callback function to calculate the derived value.
In Svelte components, you can use the $store syntax to subscribe to derived stores automatically.
Derived stores automatically update when their dependencies change.
You can derive from a single store or multiple stores.
The callback receives the current values of the dependencies and returns the derived value.
Use
$storein components to auto-subscribe and reactively update the UI.