offline docs

offline-docs/alpinejs/directives/data.md

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+# Alpine.js Documentation - Directives
+
+Alpine directives are attributes that you can add to HTML elements to give them special behavior.
+
+## [x-data](/directives/data)
+
+Everything in Alpine starts with the `x-data` directive.
+
+`x-data` defines a chunk of HTML as an Alpine component and provides the reactive data for that component to reference.
+
+Here's an example of a contrived dropdown component:
+
+```
+<div x-data="{ open: false }">
+
+
+n<button @click="open = ! open">Toggle Content</button>
+
+
+n<div x-show="open">
+
+
+nContent...
+
+
+n</div>
+
+
+n</div>
+```
+
+Don't worry about the other directives in this example (`@click` and `x-show`), we'll get to those in a bit. For now, let's focus on `x-data`.
+
+### [Scope](#scope)
+
+Properties defined in an `x-data` directive are available to all element children. Even ones inside other, nested `x-data` components.
+
+For example:
+
+```
+<div x-data="{ foo: 'bar' }">
+
+
+n<span x-text="foo"><!-- Will output: "bar" --></span>
+
+
+n<div x-data="{ bar: 'baz' }">
+
+
+n<span x-text="foo"><!-- Will output: "bar" --></span>
+
+
+n<div x-data="{ foo: 'bob' }">
+
+
+n<span x-text="foo"><!-- Will output: "bob" --></span>
+
+
+n</div>
+
+
+n</div>
+
+
+n</div>
+```
+
+### [Methods](#methods)
+
+Because `x-data` is evaluated as a normal JavaScript object, in addition to state, you can store methods and even getters.
+
+For example, let's extract the "Toggle Content" behavior into a method on `x-data`.
+
+```
+<div x-data="{ open: false, toggle() { this.open = ! this.open } }">
+
+
+n<button @click="toggle()">Toggle Content</button>
+
+
+n<div x-show="open">
+
+
+nContent...
+
+
+n</div>
+
+
+n</div>
+```
+
+Notice the added `toggle() { this.open = ! this.open }` method on `x-data`. This method can now be called from anywhere inside the component.
+
+You'll also notice the usage of `this.` to access state on the object itself. This is because Alpine evaluates this data object like any standard JavaScript object with a `this` context.
+
+If you prefer, you can leave the calling parenthesis off of the `toggle` method completely. For example:
+
+```
+<!-- Before -->
+
+
+n<button @click="toggle()">...</button>
+
+
+n<!-- After -->
+
+
+n<button @click="toggle">...</button>
+```
+
+### [Getters](#getters)
+
+JavaScript [getters](https://developer.mozilla.org/en-US/docs/Web/JavaScript/Reference/Functions/get) are handy when the sole purpose of a method is to return data based on other state.
+
+Think of them like "computed properties" (although, they are not cached like Vue's computed properties).
+
+Let's refactor our component to use a getter called `isOpen` instead of accessing `open` directly.
+
+```
+<div x-data="{
+
+
+nopen: false,
+
+
+nget isOpen() { return this.open },
+
+
+ntoggle() { this.open = ! this.open },
+
+
+n}">
+
+
+n<button @click="toggle()">Toggle Content</button>
+
+
+n<div x-show="isOpen">
+
+
+nContent...
+
+
+n</div>
+
+
+n</div>
+```
+
+Notice the "Content" now depends on the `isOpen` getter instead of the `open` property directly.
+
+In this case there is no tangible benefit. But in some cases, getters are helpful for providing a more expressive syntax in your components.
+
+### [Data-less components](#data-less-components)
+
+Occasionally, you want to create an Alpine component, but you don't need any data.
+
+In these cases, you can always pass in an empty object.
+
+```
+<div x-data="{}">
+```
+
+However, if you wish, you can also eliminate the attribute value entirely if it looks better to you.
+
+```
+<div x-data>
+```
+
+### [Single-element components](#single-element-components)
+
+Sometimes you may only have a single element inside your Alpine component, like the following:
+
+```
+<div x-data="{ open: true }">
+
+
+n<button @click="open = false" x-show="open">Hide Me</button>
+
+
+n</div>
+```
+
+In these cases, you can declare `x-data` directly on that single element:
+
+```
+<button x-data="{ open: true }" @click="open = false" x-show="open">
+
+
+nHide Me
+
+
+n</button>
+```
+
+### [Re-usable Data](#re-usable-data)
+
+If you find yourself duplicating the contents of `x-data`, or you find the inline syntax verbose, you can extract the `x-data` object out to a dedicated component using `Alpine.data`.
+
+Here's a quick example:
+
+```
+<div x-data="dropdown">
+
+
+n<button @click="toggle">Toggle Content</button>
+
+
+n<div x-show="open">
+
+
+nContent...
+
+
+n</div>
+
+
+n</div>
+
+
+n<script>
+
+
+ndocument.addEventListener('alpine:init', () => {
+
+
+nAlpine.data('dropdown', () => ({
+
+
+nopen: false,
+
+
+ntoggle() {
+
+
+nthis.open = ! this.open
+
+
+n},
+
+
+n}))
+
+
+n})
+
+
+n</script>
+```
+
+[→ Read more about `Alpine.data(...)`](/globals/alpine-data)
+
+Code highlighting provided by [Torchlight](https://torchlight.dev/)