Custom stores

As long as an object correctly implements the subscribe method, it’s a store. Beyond that, anything goes. It’s very easy, therefore, to create custom stores with domain-specific logic.

For example, the count store from our earlier example could include increment, decrement and reset methods and avoid exposing set and update:

  1. function createCount() {
  2.     const { subscribe, set, update } = writable(0);
  4.     return {
  5.         subscribe,
  6.         increment: () => update(n => n + 1),
  7.         decrement: () => update(n => n - 1),
  8.         reset: () => set(0)
  9.     };
  10. }