Encapsulating Logic with Custom Stores

Snippet

Encapsulating Logic with Custom Stores

A custom store is any object that implements a 'subscribe' method. By wrapping a standard writable store and exposing only specific methods, you can encapsulate domain logic and prevent external code from directly setting arbitrary values.

snippet.js

javascript

import { writable } from 'svelte/store';
 
function createCounter() {
  const { subscribe, update } = writable(0);
  return {
    subscribe,
    increment: () => update(n => n + 1),
    reset: () => update(() => 0)
  };
}
export const count = createCounter();

svelte

Breakdown

return { subscribe, ... }

By returning 'subscribe', the object adheres to the Svelte store contract.

increment: () => update(...)

Exposes a controlled way to modify the state without giving full access to 'set'.

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Encapsulating Logic with Custom Stores

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