pico-vue is a fork of petite-vue, which is an alternative distribution of Vue optimized for progressive enhancement. It provides the same template syntax and reactivity mental model as standard Vue. However, it is specifically optimized for "sprinkling" a small amount of interactions on an existing HTML page rendered by a server framework. See more details on how it differs from standard Vue.
- Only ~6kb
- Vue-compatible template syntax
- DOM-based, mutates in place
- Driven by
@vue/reactivity
petite-vueit's not mantained anymore, hence we will provide bug fixes and handle feature requests. Feel free to open issue or PR.- this fork is focused on web components, but we will provide new generic features too
pico-vue can be used without a build step. Simply load it from a CDN:
<script src="https://unpkg.com/pico-vue" defer init></script>
<!-- anywhere on the page -->
<div v-scope="{ count: 0 }">
{{ count }}
<button @click="count++">inc</button>
</div>
<!-- another example -->
<textarea
v-scope="{width: $el.offsetWidth, height: $el.offsetHeight}"
@click="width = $el.offsetWidth; height = $el.offsetHeight;"
>
{{ width }} × {{ height }}
</textarea>- Use
v-scopeto mark regions on the page that should be controlled bypico-vue. - The
deferattribute makes the script execute after HTML content is parsed. - The
initattribute tellspico-vueto automatically query and initialize all elements that havev-scopeon the page.
If you don't want the auto init, remove the init attribute and move the scripts to end of <body>:
<script src="https://unpkg.com/pico-vue"></script>
<script>
PetiteVue.createApp().mount()
</script>Or, use the ES module build:
<script type="module">
import { createApp } from 'https://unpkg.com/pico-vue?module'
createApp().mount()
</script>The short CDN URL is meant for prototyping. For production usage, use a fully resolved CDN URL to avoid resolving and redirect cost:
- Global build:
https://unpkg.com/[email protected]/dist/pico-vue.iife.js- exposes
PetiteVueglobal, supports auto init
- exposes
- ESM build:
https://unpkg.com/[email protected]/dist/pico-vue.es.js- Must be used with
<script type="module">
- Must be used with
The createApp function accepts a data object that serves as the root scope for all expressions. This can be used to bootstrap simple, one-off apps:
<script type="module">
import { createApp } from 'https://unpkg.com/pico-vue?module'
createApp({
// exposed to all expressions
count: 0,
// getters
get plusOne() {
return this.count + 1
},
// methods
increment() {
this.count++
}
}).mount()
</script>
<!-- v-scope value can be omitted -->
<div v-scope>
<p>{{ count }}</p>
<p>{{ plusOne }}</p>
<button @click="increment">increment</button>
</div>Note v-scope doesn't need to have a value here and simply serves as a hint for pico-vue to process the element.
You can specify a mount target (selector or element) to limit pico-vue to only that region of the page:
createApp().mount('#only-this-div')This also means you can have multiple pico-vue apps to control different regions on the same page:
createApp({
// root scope for app one
}).mount('#app1')
createApp({
// root scope for app two
}).mount('#app2')The concept of "Components" are different in pico-vue, as it is much more bare-bones.
First, reusable scope logic can be created with functions:
<script type="module">
import { createApp } from 'https://unpkg.com/pico-vue?module'
function Counter(props) {
return {
count: props.initialCount,
inc() {
this.count++
},
mounted() {
console.log(`I'm mounted!`)
}
}
}
createApp({
Counter
}).mount()
</script>
<div v-scope="Counter({ initialCount: 1 })" @vue:mounted="mounted">
<p>{{ count }}</p>
<button @click="inc">increment</button>
</div>
<div v-scope="Counter({ initialCount: 2 })">
<p>{{ count }}</p>
<button @click="inc">increment</button>
</div>If you also want to reuse a piece of template, you can provide a special $template key on a scope object. The value can be the template string, or an ID selector to a <template> element:
<script type="module">
import { createApp } from 'https://unpkg.com/pico-vue?module'
function Counter(props) {
return {
$template: '#counter-template',
count: props.initialCount,
inc() {
this.count++
}
}
}
createApp({
Counter
}).mount()
</script>
<template id="counter-template">
My count is {{ count }}
<button @click="inc">++</button>
</template>
<!-- reuse it -->
<div v-scope="Counter({ initialCount: 1 })"></div>
<div v-scope="Counter({ initialCount: 2 })"></div>The <template> approach is recommended over inline strings because it is more efficient to clone from a native template element.
You can listen to the special vue:mounted and vue:unmounted lifecycle events for each element:
<div
v-if="show"
@vue:mounted="console.log('mounted on: ', $el)"
@vue:unmounted="console.log('unmounted: ', $el)"
></div>represent the current element
represent the element of v-scope
Use v-effect to execute reactive inline statements:
<div v-scope="{ count: 0 }">
<div v-effect="$el.textContent = count"></div>
<button @click="count++">++</button>
</div>The effect uses count which is a reactive data source, so it will re-run whenever count changes.
Another example of replacing the todo-focus directive found in the original Vue TodoMVC example:
<input v-effect="if (todo === editedTodo) $el.focus()" /><div v-scope="[{name: 'rush', items: 3}, {...}]">
<!-- v-for loop on arrays and objects -->
<div v-for="customer in $data" :key="customer.name">
<!-- print values -->
<p v-for="value in customer" :key="value"> {{ value }} </p>
<!-- print values and keys -->
<p v-for="(value, key) in customer" :key="value"> {{ key }}: {{ value }} </p>
</div>
<button @click="$data.push({name: 'random', ...})">add</button>
</div>avoid flash rendreng which happen until petite-vue loaded, after it load it will remove these directives
This directive is only needed in no-build-step setups
<style>
[v-cloak] {
display: none;
}
</style>
<div v-cloak>
{{ message }}
</div>You can use the reactive method (re-exported from @vue/reactivity) to create global state singletons:
<script type="module">
import { createApp, reactive } from 'https://unpkg.com/pico-vue?module'
const store = reactive({
count: 0,
inc() {
this.count++
}
})
// manipulate it here
store.inc()
createApp({
// share it with app scopes
store
}).mount()
</script>
<div v-scope="{ localCount: 0 }">
<p>Global {{ store.count }}</p>
<button @click="store.inc">increment</button>
<p>Local {{ localCount }}</p>
<button @click="localCount++">increment</button>
</div>Use watchEffect to re-run a function every time its dependencies changes.
import { watchEffect, reactive } from 'https://unpkg.com/pico-vue?module'
const store = reactive({
count: 0,
})
watchEffect( () => console.log(store.count))
store.count++Custom directives are also supported but with a different interface:
const myDirective = (ctx) => {
// the element the directive is on
ctx.el
// the raw value expression
// e.g. v-my-dir="x" then this would be "x"
ctx.exp
// v-my-dir:foo -> "foo"
ctx.arg
// v-my-dir.mod -> { mod: true }
ctx.modifiers
// evaluate the expression and get its value
ctx.get()
// evaluate arbitrary expression in current scope
ctx.get(`${ctx.exp} + 10`)
// run reactive effect
ctx.effect(() => {
// this will re-run every time the get() value changes
console.log(ctx.get())
})
return () => {
// cleanup if the element is unmounted
}
}
// register the directive
createApp().directive('my-dir', myDirective).mount()This is how v-html is implemented:
const html = ({ el, get, effect }) => {
effect(() => {
el.innerHTML = get()
})
}You can use custom delimiters by passing $delimiters to your root scope. This is useful when working alongside a server-side templating language that also uses mustaches:
createApp({
$delimiters: ['${', '}']
}).mount()You can write custome directive then distrbute it as a package, then add it to create vue, like:
<div v-scope="{counter: 0}" v-log="inside pico-vue scope">
<button @click="counter++">increase</button>
</div>
<script type="module">
import log from './log'
import { createApp } from 'pico-vue'
createApp().use(log).mount()
</script>A plugin code similar to vue plugins code:
// inside log.js plugin file
export default {
install: (app, options) => {
app.directive('log', ({exp}) => {
console.log(exp)
})
}
}Check out the examples directory.
v-scopev-effect@vue:mounted&@vue:unmountedevents$rootrefers to the component root element
- In expressions,
$elpoints to the current element the directive is bound to (instead of component root element which accessed by$root) createApp()accepts global state instead of a component- Components are simplified into object-returning functions
- Custom directives have a different interface
- exported
watchEffect
{{ }}text bindings (configurable with custom delimiters)v-bind(including:shorthand and class/style special handling)v-on(including@shorthand and all modifiers)v-model(all input types + non-string:valuebindings)v-if/v-else/v-else-ifv-forv-showv-htmlv-textv-prev-oncev-cloakreactive()nextTick()- Template refs
Some features are dropped because they have a relatively low utility/size ratio in the context of progressive enhancement. If you need these features, you should probably just use standard Vue.
ref(),computed()etc.- Render functions (
pico-vuehas no virtual DOM) - Reactivity for Collection Types (Map, Set, etc., removed for smaller size)
- Transition, KeepAlive, Teleport, Suspense
v-fordeep destructurev-on="object"v-is&<component :is="xxx">v-bind:styleauto-prefixing
The point of petite-vue is not just about being small. It's about using the optimal implementation for the intended use case (progressive enhancement).
Standard Vue can be used with or without a build step. When using a build setup (e.g. with Single-File Components), we pre-compile all the templates so there's no template processing to be done at runtime. And thanks to tree-shaking, we can ship optional features in standard Vue that doesn't bloat your bundle size when not used. This is the optimal usage of standard Vue, but since it involves a build setup, it is better suited when building SPAs or apps with relatively heavy interactions.
When using standard Vue without a build step and mounting to in-DOM templates, it is much less optimal because:
- We have to ship the Vue template compiler to the browser (13kb extra size)
- The compiler will have to retrieve the template string from already instantiated DOM
- The compiler then compiles the string into a JavaScript render function
- Vue then replaces existing DOM templates with new DOM generated from the render function.
petite-vue avoids all this overhead by walking the existing DOM and attaching fine-grained reactive effects to the elements directly. The DOM is the template. This means petite-vue is much more efficient in progressive enhancement scenarios.
This is also how Vue 1 worked. The trade-off here is that this approach is coupled to the DOM and thus not suitable for platform agnostic rendering or JavaScript SSR. We also lose the ability to work with render functions for advanced abstractions. However as you can probably tell, these capabilities are rarely needed in the context of progressive enhancement.
petite-vue is indeed addressing a similar scope to Alpine, but aims to be (1) even more minimal and (2) more Vue-compatible.
-
petite-vueis around half the size of Alpine. -
petite-vuehas no transition system (maybe this can be an opt-in plugin). -
Although Alpine largely resembles Vue's design, there are various cases where the behavior is different from Vue itself. It may also diverge more from Vue in the future. This is good because Alpine shouldn't have to restrict its design to strictly follow Vue - it should have the freedom to develop in a direction that makes sense for its goals.
In comparison,
petite-vuewill try to align with standard Vue behavior whenever possible so that there is less friction moving to standard Vue if needed. It's intended to be part of the Vue ecosystem to cover the progressive enhancement use case where standard Vue is less optimized for nowadays.
petite-vue evaluates JavaScript expressions in the templates. This means if petite-vue is mounted on a region of the DOM that contains non-sanitized HTML from user data, it may lead to XSS attacks. If your page renders user-submitted HTML, you should prefer initializing petite-vue using explicit mount target so that it only processes parts that are controlled by you. You can also sanitize any user-submitted HTML for the v-scope attribute.
petite-vue evaluates the expressions using new Function(), which may be prohibited in strict CSP settings. There is no plan to provide a CSP build because it involves shipping an expression parser which defeats the purpose of being lightweight. If you have strict CSP requirements, you should probably use standard Vue and pre-compile the templates.
MIT