asset_import_hook
v0.4.10
Published
AssetImport Phoenix LiveView hook for dynamic asset loading
Downloads
3
Readme
AssetImport
Webpack asset imports directly in Elixir code. For example in Phoenix controllers/views/templates or LiveView's.
Features
- Only load assets that are used for current render.
- Helps to avoid assets over, under, or double fetching.
- Optimal asset packaging and cache reuse with Webpack code splitting.
- Supports Phoenix LiveView's by loading assets dynamically.
- Supports mix dependencies that are using
asset_import
.
Installation
The package can be installed by adding asset_import
to your list of dependencies in mix.exs
:
def deps do
[
{:asset_import, "~> 0.4.10"}
]
end
Usage
/* assets/css/forms.css */
form {
/* a lot of form styling, or import bootstrap `_forms.scss` etc */
}
// assets/js/login_form.js
import "../css/forms.css"
// some login form specific javascript here
Anywhere in your views, templates, or LiveView renders:
<div>
<%= if @logged_in do %>
<div>My profile..</div>
<% else %>
<!--
You can use <% asset_import @conn, "js/login_form" %> (without =),
if you are not using this template in LiveView. It will save some bytes from your html.
-->
<%= asset_import @conn, "js/login_form" %>
<!--
Inside LiveView use @socket instead @conn
-->
<%= asset_import @socket, "js/login_form" %>
<form>Login form..</form>
<% end %>
</div>
Usage with LiveView hooks that guarantees that code is always loaded before hook usage:
<div>
<%= if @logged_in do %>
<div>My profile..</div>
<% else %>
<form data-hook="MyHook" phx-hook="AssetHook" data-assets="<%= asset_hook(@socket, "js/myHook") %>">
Login form..
</form>
<% end %>
</div>
Assets js/login_form.js
and css/forms.css
are only loaded when user is not logged in.
Setup
1. Configuration
Typical asset_import
config:
# config/config.exs
config :asset_import, MyAppWeb.Assets,
assets_base_url: "/",
assets_path: Path.expand("assets"),
manifest_path: Path.expand("priv/static/manifest.json"),
entrypoints_path: Path.expand("assets/entrypoints.json")
Replace phoenix watcher from webpack
to nodemon
:
# config/dev.exs
config :my_app, MyAppWeb.Endpoint,
debug_errors: true,
code_reloader: true,
check_origin: false,
watchers: [node: ["node_modules/nodemon/bin/nodemon.js", cd: Path.expand("../assets", __DIR__)]]
Disable entrypoints file generation in test.
# config/test.exs
config :asset_import, entrypoints_path: :disabled
2. Create an assets module
defmodule MyAppWeb.Assets do
use AssetImport,
assets_path: "assets" # optional, defaults to "assets"
use AwesomeUiComponents.Assets # add dependency assets
end
3. Use your assets module in web module
defmodule MyAppWeb do
..
def view do
quote do
..
use MyAppWeb.Assets
..
end
end
..
end
4. Import file macros to your layout view
defmodule MyAppWeb.LayoutView do
use MyAppWeb, :view
import MyAppWeb.Assets.Files
end
5. Add scripts and styles to layout
<!-- Content rendering has to execute before scripts and styles -->
<% body = render "body.html", assigns %>
<html>
<head>
<!-- Styles for current page (render blocking) -->
<%= asset_styles() %>
<!-- Optional: Preload unused styles and scripts -->
<%= preload_asset_styles() %>
<%= preload_asset_scripts() %>
</head>
<body>
<%= body %>
<!-- Scripts for current page -->
<%= asset_scripts() %>
</body>
</html>
Or
<!-- Content rendering has to execute before scripts and styles -->
<% body = render "body.html", assigns %>
<html>
<head>
<!-- Styles for current page (render blocking) -->
<%= for path <- asset_style_files() do %>
<link rel="stylesheet" href="<%= path %>" />
<% end %>
<!-- Optional: Preload unused styles and scripts -->
<%= for path <- unused_asset_style_files() do %>
<link rel="preload" href="<%= path %>" as="style">
<% end %>
<%= for path <- unused_asset_script_files() do %>
<link rel="preload" href="<%= path %>" as="script">
<% end %>
</head>
<body>
<%= body %>
<!-- Scripts for current page -->
<%= for path <- asset_script_files() do %>
<script type="text/javascript" src="<%= path %>"></script>
<% end %>
</body>
</html>
6. Add LiveView hook (only when LiveView is used)
import LiveSocket from "phoenix_live_view"
import Socket from "phoenix"
import AssetImport from "asset_import_hook"
let liveSocket = new LiveSocket("/live", Socket, { AssetImport })
liveSocket.connect()
7. Webpack setup
Copy example_assets/*
to your project assets or adjust existing files manually:
// assets/nodemon.json { "watch": ["entrypoints.json", "webpack.config.js"], "exec": "node_modules/webpack/bin/webpack.js --color --mode development --watch-stdin" }
// assets/package.json { .. "dependencies": { .. "asset_import_hook": "0.4.10" // only when LiveView is used .. }, "devDependencies": { .. "nodemon": "1.19.2", "uglifyjs-webpack-plugin": "2.2.0", .. } }
// assets/webpack.config.js .. 8: const entrypoints = require('./entrypoints.json') || {}; 9: 10: if (Object.keys(entrypoints).length === 0) { 11: console.log('No entrypoints'); 12: process.exit(); 13: return; 14: } .. 23: runtimeChunk: 'single', 24: chunkIds: 'natural', 25: concatenateModules: true, 26: splitChunks: { 27: chunks: 'all', 28: minChunks: 1, 29: minSize: 0 30: } 31: }, 32: entry: entrypoints, 33: output: { 34: filename: 'js/[id]-[contenthash].js', 35: chunkFilename: 'js/[id]-[contenthash].js', 36: path: path.resolve(__dirname, '../priv/static') 37: }, 38: plugins: [ 39: new MiniCssExtractPlugin({ 40: filename: 'css/[id]-[contenthash].css', 41: chunkFilename: 'css/[id]-[contenthash].css', 42: }), 43: new ManifestPlugin({ fileName: 'manifest.json' }), ..