You can not select more than 25 topics Topics must start with a letter or number, can include dashes ('-') and can be up to 35 characters long.
svelte/documentation/tutorial/08-stores/01-writable-stores/text.md

28 lines
1009 B

---
title: Writable stores
---
Not all application state belongs inside your application's component hierarchy. Sometimes, you'll have values that need to be accessed by multiple unrelated components, or by a regular JavaScript module.
In Svelte, we do this with _stores_. A store is simply an object with a `subscribe` method that allows interested parties to be notified whenever the store value changes. In `App.svelte`, `count` is a store, and we're setting `countValue` in the `count.subscribe` callback.
Click the `stores.js` tab to see the definition of `count`. It's a _writable_ store, which means it has `set` and `update` methods in addition to `subscribe`.
Now go to the `Incrementer.svelte` tab so that we can wire up the `+` button:
```js
function increment() {
count.update((n) => n + 1);
}
```
Clicking the `+` button should now update the count. Do the inverse for `Decrementer.svelte`.
Finally, in `Resetter.svelte`, implement `reset`:
```js
function reset() {
count.set(0);
}
```