[](https://hex.pm/packages/live_vue)
[](https://hexdocs.pm/live_vue)
[](https://github.com/Valian/live_vue)
# LiveVue
Vue inside Phoenix LiveView with seamless end-to-end reactivity.
## Resources
- [HexDocs](https://hexdocs.pm/live_vue)
- [HexPackage](https://hex.pm/packages/live_vue)
- [Phoenix LiveView](https://github.com/phoenixframework/phoenix_live_view)
## Table of content
- [Features](#features)
- [Resources](#resources)
- [Example](#example)
- [Installation](#installation)
- [Usage](#usage)
- [Deployment](#deployment)
- [FAQ](#faq)
## Features
- ⚡ **End-To-End Reactivity** with LiveView
- 🔋 **Server-Side Rendered** (SSR) Vue
- 🐌 **Lazy-loading** Vue Components
- 🪄 **Sigil** as an [Alternative LiveView DSL](#using-v-sigil-to-inline-vue-components)
- 🦄 **Tailwind** Support
- 💀 **Dead View** Support
- 🦥 **Slot Interoperability**
- 🚀 **Amazing DX** with Vite
## Example
After installation, you can use Vue components in the same way as you'd use functional LiveView components. You can even handle Vue events with `JS` hooks! All the `phx-click`, `phx-change` attributes works inside Vue components as well.
```vue
<script setup lang="ts">
import {ref} from "vue"
const props = defineProps<{count: number}>()
const emit = defineEmits<{inc: [{value: number}]}>()
const diff = ref<string>("1")
</script>
<template>
Current count
<div class="text-2xl text-bold">{{ props.count }}</div>
<label class="block mt-8">Diff: </label>
<input v-model="diff" class="my-4" type="range" min="1" max="10" />
<button
@click="emit('inc', {value: parseInt(diff)})"
class="bg-black text-white rounded p-2"
>
Increase counter by {{ diff }}
</button>
</template>
```
```elixir
defmodule LiveVueExamplesWeb.LiveCounter do
use LiveVueExamplesWeb, :live_view
def render(assigns) do
~H"""
<.vue
count={@count}
v-component="Counter"
v-socket={@socket}
v-on:inc={JS.push("inc")}
/>
"""
end
def mount(_params, _session, socket) do
{:ok, assign(socket, :count, 0)}
end
def handle_event("inc", %{"value" => diff}, socket) do
{:noreply, update(socket, :count, &(&1 + diff))}
end
end
```
## Why?
Phoenix Live View makes it possible to create rich, interactive web apps without writing JS.
But once you'll need to do anything even slightly complex on the client-side, you'll end up writing lots of imperative, hard-to-maintain hooks.
LiveVue allows to create hybrid apps, where part of the session state is on the server and part on the client.
### Reasons why you'd like to use LiveVue
- Your hooks are starting to look like jQuery
- You have a complex local state
- You'd like to use a massive Vue ecosystem
- You want transitions, graphs etc.
- You simply like Vue 😉
## Installation
See [Installation](INSTALLATION.md).
## Usage
By default, vue components should be placed either inside `assets/vue` directory or colocated with your Elixir files. You can configure that behaviour by changing `assets/vue/index.js` and `use LiveVue.Components, vue_root: ["your/vue/dir"]`.
### Basic usage
To render vue component from HEEX, you have to use `<.vue>` function with these attributes:
| Attribute | Example | Required | Description |
| --------------------- | ------------------------------------------------------ | --------------- | ---------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------- |
| v-component | `v-component="Counter"`, `v-component="helpers/modal"` | yes | Name of the component to render. Must match key defined in `components` passed to `getHooks`. By default you can use both filename or a full file path without extension, relative to `assets/vue` or `lib/my_app_web` |
| v-socket | `v-socket={@socket}` | Yes in LiveView | Used to determine if SSR is needed. Should be always included in LiveViews |
| v-ssr | `v-ssr={true}` | no | Defaults to `Application.get_env(:live_vue, :ssr, true)` |
| v-on:event={@handler} | `v-on:close={JS.toggle()}` | no | Handle component event by invoking JS hook. @handler has to come from `JS` module. See Usage section for more. |
| prop={@value} | `name="liveVue"`, `count={@count}`, `{%{count: 123}}` | no | All other attributes will be passed to vue component as props. Values have to be serializable to JSON, so structures have to implement `Jason.Encoder` protocol. |
### Shortcut
Instead of writing `<.vue v-component="Counter">` you can use shortcut `<.Counter>`. Function names are generated based on filenames of found `.vue` files, so `assets/vue/helpers/nested/Modal.vue` will generate helper `<.Modal>`. If there are multiple `.vue` files with equal names, use `<.vue v-component="path/to/file">`
### Passing props
You pass props in the same way as with functional components in Elixir. All 3 examples does exactly the same.
```elixir
<.vue
count={@count}
name={@name}
v-component="Counter"
v-socket={@socket}
/>
<.vue
v-component="Counter"
v-socket={@socket}
{%{count: @count, name: @name}}
/>
<.Counter
count={@count}
name={@name}
v-socket={@socket}
/>
```
### Handling events
All regular phoenix hooks like `phx-click`, `phx-submit` work as expected.
To keep components DRY you can define vue handlers using `v-on:eventname={JS.handler()}` syntax.
All attributes starting with `v-on:` are attached as emit handlers to Vue components and executed in the same way as Phoenix does it.
`JS.push("someName")` is a special case - if JS.push defines no value, it will be replaced by the emit payload.
```elixir
<.vue v-on:submit={JS.push("submit")} v-component="SomeForm" v-socket={@socket} />
<.vue
v-on:shoot={JS.push("shoot")}
v-on:close={JS.hide()}
v-component="SomeGame"
v-socket={@socket}
/>
```
### Passing slots
You can even pass slots to the vue component! They're passed to vue as raw HTML, so hooks in the slots won't work. Each slot is wrapped in a div due to technical limitations.
- Default slot can be passed as `:inner_block` and rendered inside Vue components as `<slot />`.
- Named slots can be passed by using `<:slot_name>Content</:slot_name>` syntax are rendered using `<slot name="slot_name" />` syntax.
- Slots will be kept in sync, as expected.
An example:
```elixir
<.Card title="The coldest sunset" v-socket={@socket}>
<p>This is card content passed from phoenix!</p>
<p>Even icons are working! <.icon name="hero-information-circle-mini" /></p>
<:footer>And this is a footer from phoenix</:footer>
</.Card>
```
```vue
<template>
<slot></slot>
Footer:
<slot name="footer"></slot>
</template>
```
### Dead views vs Live views
You can use `<.vue>` components in dead views. Of course, there will be no updates on assign changes, since there is no websocket connection established to support it.
v-socket={@socket} is not required in dead views.
### Note on SSR
Vue SSR is compiled down into string concatenation, so it's quite fast 😉
In development it's recommended to use `config :live_vue, ssr_module: LiveVue.SSR.ViteJS`. It does HTTP call to vite `/ssr_render` endpoint added by LiveVue plugin, which in turn uses vite [ssrLoadModule](https://vitejs.dev/guide/ssr) for efficient compilation.
In production it's recommended to use `config :live_vue, ssr_module: LiveVue.SSR.NodeJS` which uses `NodeJS` package directly talking with a JS process with a in-memory server bundle. By default, SSR bundle is saved to `priv/vue/server.js`.
### Handling custom Phoenix events client side
You can use function `useLiveVue` to access root phoenix element where Vue component was routed.
API of that object is described in [Phoenix docs](https://hexdocs.pm/phoenix_live_view/js-interop.html#client-hooks-via-phx-hook).
Example
```vue
<script>
import {useLiveVue} from "live_vue"
const hook = useLiveVue()
hook.pushEvent("hello", {value: "from Vue"})
</script>
```
### Using ~V sigil to inline Vue components
We can go one step further and use LiveVue as an alternative to the standard LiveView DSL. This idea is taken from `LiveSvelte`.
Take a look at the following example:
```elixir
defmodule ExampleWeb.LiveSigil do
use ExampleWeb, :live_view
def render(assigns) do
~V"""
<script setup lang="ts">
import {ref} from "vue"
const props = defineProps<{count: number}>()
const diff = ref<number>(1)
</script>
<template>
Current count
<div class="text-2xl text-bold">{{ props.count }}</div>
<label class="block mt-8">Diff: </label>
<input v-model="diff" class="mt-4" type="range" min="1" max="10">
<button
phx-click="inc"
:phx-value-diff="diff"
class="mt-4 bg-black text-white rounded p-2 block">
Increase counter {{ diff }}
</button>
</template>
"""
end
def mount(_params, _session, socket) do
{:ok, assign(socket, count: 0)}
end
def handle_event("inc", %{"diff" => diff}, socket) do
{:noreply, update(socket, :count, &(&1 + String.to_integer(diff)))}
end
end
```
Use the `~V` sigil instead of `~H` and your LiveView will be Vue instead of an HEEx template.
### Lazy loading Vue Components
Lazy loading Vue components is fully supported. You just need to return function returning promise in `components` passed to `getHooks(components)`.
It can be done by using `eager: false` in `import.meta.glob('./yourdir/*.vue', { eager: false, import: 'default' })` or by explicitly constructing components object. If SSR is enabled, all related JS and CSS files will be preloaded in HTML.
```javascript
import component1 from "./Component1.vue"
import component2 from "./Component2.vue"
const entryComponents = {
Component1: component1,
Component2: component2,
Component3Lazy: () => import("./Component3.vue"),
}
// in app.js
const hooks = getHooks(entryComponents)
```
### Customize Vue app
If you want to initialize Vue app in any way, by eg. adding plugins or directives, you can customize it easily in `assets/vue/index.js` setup function.
```javascript
// in assets/vue/index.js
// ...
// import { createPinia } from "pinia"
// const pinia = createPinia()
export default createLiveVue({
resolve: name => {
// ...
},
setup: ({ createApp, component, props, slots, plugin, el }) => {
const app = createApp({ render: () => h(component, props, slots) })
app.use(plugin)
// add your own plugins here
// app.use(pinia)
app.mount(el)
return app
},
})
```
You can completely change the default initialization method by adjusting `setup` to your needs.
Note: `setup` is called also in SSR mode. You can adjust initialization based on `ssr` flag passed as an argument to setup.
```javascript
export default createLiveVue({
setup: ({ createApp, component, props, slots, plugin, el, ssr }) => {
const app = createApp({ render: () => h(component, props, slots) })
if (ssr) { console.log("Creating app for SSR") }
app.use(plugin)
app.mount(el)
return app
},
})
```
Context object passed to `setup` has following keys:
| Property | Descriptor |
| ----------- | ------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------ |
| `createApp` | Either [`createApp()`](https://vuejs.org/api/application#createapp) or [`createSSRApp()`](https://vuejs.org/api/application#createssrapp) depending on whether or not SSR is enabled |
| `component` | The vue compoenent that is to be rendered |
| `props` | The props passed to the component |
| `slots` | The slots passed to the component |
| `plugin` | A `live_vue` plugin that makes it possible to use `useLiveVue` provider |
| `el` | The html element in which the vue app should be mounted |
| `ssr` | Boolean indicating if setup is running in SSR or not |
## Relation to LiveSvelte
This project is heavily inspired by ✨ [LiveSvelte](https://github.com/woutdp/live_svelte) ✨. Both projects try to solve the same problem. LiveVue was started as a fork of LiveSvelte with adjusted ESbuild settings, and evolved to use Vite and a slightly different syntax. I strongly believe more options are always better, and since I love Vue and it's ecosystem I've decided to give it a go 😉
You can read more about differences between Vue and Svelte [in FAQ](#differences-from-livesvelte).
## LiveVue Development
### Local Setup
Ensure you have node installed. Clone the repo and run `mix setup`. You can then run `mix assets.watch` to start a watcher for the assets.
#### Example Project
You can use `/example_project` as a way to test `live_vue` locally.
#### Custom Project
You can also use your own project.
Clone `live_vue` to the parent directory of the project you want to test it in.
Inside `mix.exs`
```elixir
{:live_vue, path: "../live_vue"},
```
Inside `assets/package.json`
```javascript
"live_vue": "file:../../live_vue",
```
### Building Static Files
Make the changes in `/assets/js` and run:
```bash
mix assets.build
```
Or run the watcher:
```bash
mix assets.watch
```
### Releasing
Release is done with `expublish` package.
- Write version changelog in untracked `RELEASE.md` file
- Update version in `INSTALLATION.md`
Run
```bash
git add INSTALLATION.md
git commit -m "INSTALLATION version bump"
# to ensure everything works fine
mix expublish.minor --dry-run --allow-untracked --branch=main
# to publish everything
mix do assets.build, expublish.minor --allow-untracked --branch=main
```
## Deployment
Deploying a LiveVue app is the same as deploying a regular Phoenix app, except that you will need to ensure that `nodejs` (version 19 or later) is installed in your production environment.
The below guide shows how to deploy a LiveVue app to [Fly.io](https://fly.io/), but similar steps can be taken to deploy to other hosting providers.
You can find more information on how to deploy a Phoenix app [here](https://hexdocs.pm/phoenix/deployment.html).
### Deploying on Fly.io
The following steps are needed to deploy to Fly.io. This guide assumes that you'll be using Fly Postgres as your database. Further guidance on how to deploy to Fly.io can be found [here](https://fly.io/docs/elixir/getting-started/).
1. Generate a `Dockerfile`:
```bash
mix phx.gen.release --docker
```
2. Modify the generated `Dockerfile` to install `curl`, which is used to install `nodejs` (version 19 or greater), and also add a step to install our `npm` dependencies:
```diff
# ./Dockerfile
...
# install build dependencies
- RUN apt-get update -y && apt-get install -y build-essential git \
+ RUN apt-get update -y && apt-get install -y build-essential git curl \
&& apt-get clean && rm -f /var/lib/apt/lists/*_*
+ # install nodejs for build stage
+ RUN curl -fsSL https://deb.nodesource.com/setup_19.x | bash - && apt-get install -y nodejs
...
COPY assets assets
+ # install all npm packages in assets directory
+ RUN cd /app/assets && npm install
...
# start a new build stage so that the final image will only contain
# the compiled release and other runtime necessities
FROM ${RUNNER_IMAGE}
RUN apt-get update -y && \
- apt-get install -y libstdc++6 openssl libncurses5 locales ca-certificates \
+ apt-get install -y libstdc++6 openssl libncurses5 locales ca-certificates curl \
&& apt-get clean && rm -f /var/lib/apt/lists/*_*
+ # install nodejs for production environment
+ RUN curl -fsSL https://deb.nodesource.com/setup_19.x | bash - && apt-get install -y nodejs
...
```
Note: `nodejs` is installed BOTH in the build stage and in the final image. This is because we need `nodejs` to install our `npm` dependencies and also need it when running our app.
3. Launch your app with the Fly.io CLI:
```bash
fly launch
```
4. When prompted to tweak settings, choose `y`:
```bash
? Do you want to tweak these settings before proceeding? (y/N) y
```
This will launch a new window where you can tweak your launch settings. In the database section, choose `Fly Postgres` and enter a name for your database. You may also want to change your database to the development configuration to avoid extra costs. You can leave the rest of the settings as-is unless you want to change them.
Deployment will continue once you hit confirm.
5. Once the deployment completes, run the following command to see your deployed app!
```bash
fly apps open
```
## FAQ
### Name sounds exactly the same as LiveView
Yes, I noticed it slightly too late to change. Some helpful reddit users pointed it out 😉
I'd suggest referring to it as `LiveVuejs` in speech, to avoid confusion.
### Differences from LiveSvelte
Both `LiveVue` and `LiveSvelte `serves the same purpose and are implemented in a very similar way. Here is a list of points to consider when choosing one over another:
- Vue uses virtual DOM, Svelte doesn't. Vue bundle is slightly bigger than Svelte because of runtime.
- Vue performance is very similar, or even better, than Svelte. Both are fast enough that you shouldn't make your decision based on it.
- Vue is working on a [Vapor mode](https://github.com/vuejs/core-vapor) without virtual DOM. Once stable I'll try to support it here.
- Svelte reactivity is done based on the compilation step figuring out dependencies. It allows for a very concise syntax, but causes problems when you'd like to keep reactivity cross-files and [has some limitations](https://thoughtspile.github.io/2023/04/22/svelte-state/). Svelte 5 Runes will be very similar to Vue `ref`.
- Vue reactivity is [based on JS Proxies](https://vuejs.org/guide/extras/reactivity-in-depth.html#how-reactivity-works-in-vue). Syntax is a bit more verbose, but there are less ways to shoot yourself in a foot 😉
- Vue is more popular than Svelte, and has a bigger ecosystem. It might be an important thing to consider when making a decision.
### Colocating Vue files alongside your LiveViews
Vue files in LiveVue have similar role as HEEX templates. In many cases it makes sense to [colocate them next to your LiveViews for better DX](https://elixirforum.com/t/discussion-about-domain-orientated-folder-structures-in-phoenix/17190).
You don't need to do anything to make it work, simply place your Vue files inside `lib/my_app_web` directory and reference them by their names or relative paths.
### How does it work?
The idea is fairly simple.
1. Phoenix [renders](https://github.com/Valian/live_vue/blob/main/lib/live_vue.ex) a `div` with props, slots and handlers as `data` attributes. In live views these are kept in sync. When SSR is enabled, it also renders the component and inlines the result in the HTML.
2. `LiveVue` [hook](https://github.com/Valian/live_vue/blob/main/assets/js/live_vue/hooks.js) `mount` callback initializes the element. It hooks up all the handlers, injects hook itself so `useLiveVue` works correctly, and mounts the Vue component.
3. On update, Phoenix only changes data attributes. Hook updates props of the element.
4. On destroy, Vue element is unmounted and garbage collected.
One thing to keep in mind is that hooks are fired only after `app.js` is fully loaded, so it might cause some delays of the initial render of the component.
### Optimizations
LiveVue introduces a number of interesting optimizations:
- Props, Handlers or slots are only send to the client if anything was changed. It's accomplished through a careful modifications of `__changed__` assign.
- We use `data-props={"#{@props |> Jason.encode()}"}` syntax (notice String interpolation) to avoid sending `data-props=` on each update
- Soon: we'll be sending only updated props
- Soon: we'll be sending only deep-diff of props (similar to LiveJson, but automated)
### Why SSR is useful?
As explained in the previous section, it takes a moment for Vue component to initialize, even if props are already inlined in the HTML.
It's done only during a "dead" render, without connected socket. It's not needed when doing live navigation - in my experience when using `<.link navigate="...">` component is rendered before displaying a new page.
## Roadmap 🎯
- [ ] Add a default handler for Vue emits to eg. automatically push them to the server without explicit `v-on` handlers.
- [ ] try to use [Igniter](https://hexdocs.pm/igniter/) as a way of installing LiveVue in a project
- [ ] `usePushEvent` - an utility similar to [`useFetch`](https://vueuse.org/core/useFetch/) making it easy to get data from `&handle_event/3 -> {:reply, data, socket}` responses
- [ ] `useLiveForm` - an utility to efforlessly use Ecto changesets & server-side validation, similar to HEEX
- [ ] `useEventHandler` - an utility automatically attaching & detaching [`handleEvent`](https://hexdocs.pm/phoenix_live_view/js-interop.html#client-hooks-via-phx-hook)
- [ ] optimize payload - send only [`json_patch`](https://hexdocs.pm/jsonpatch/readme.html) diffs of updated props
- [ ] VS code extension highlighting `~V` sigil
- [ ] Add support for Phoenix streams as props
## Credits
[LiveSvelte](https://github.com/woutdp/live_svelte)
## Star History
[](https://star-history.com/#Valian/live_vue&Date)
