vite-plugin-cdn-import-async
v1.1.0
Published
Import packages asynchronously from CDN for the vite plugin
Downloads
209
Maintainers
vajoyReadme
Vite plugin which can import modules asynchronously from CDN.
This plugin is forked from vite-plugin-cdn-import and allows you to specify modules that should be loaded in defer/async mode in addition.
Installation
npm:
npm install vite-plugin-cdn-import-async --save-devyarn:
yarn add vite-plugin-cdn-import-async -DUsage
Plugin config
Specify async or defer to mode param whthin configs of the module you want to import asynchronously from CDN:
// vite.config.js
import cdnImport from 'vite-plugin-cdn-import-async'
export default {
plugins: [
cdnImport({
modules: [
{
name: 'react',
var: 'React',
mode: 'async', // 'async' atrribute will be added to its <script> tag.
path: `https://cdn.jsdelivr.net/npm/[email protected]/umd/react.production.min.js`,
},
{
name: 'lottie-web',
var: 'lottie',
mode: 'defer', // 'defer' atrribute will be added to its <script> tag.
path: `https://cdn.jsdelivr.net/npm/[email protected]/build/player/lottie.min.js`,
},
{
name: 'axios', // Module without 'mode' param will be loaded synchronously.
var: 'axios',
path: 'https://cdn.jsdelivr.net/npm/[email protected]/dist/axios.min.js',
}
],
}),
],
}This demo will generate codes below into the output file:
<script>function __cdnImportAsyncHandler(o,n){n&&window.cdnImportAsync_loadingErrorModules.push(o);var d=new CustomEvent("asyncmoduleloaded",{detail:{module:o,isError:!!n}});window.dispatchEvent(d)}window.cdnImportAsync_loadingErrorModules=window.cdnImportAsync_loadingErrorModules||[];</script>
<script async onload="__cdnImportAsyncHandler('React')" onerror="__cdnImportAsyncHandler('React', true)" src="https://cdn.jsdelivr.net/npm/[email protected]/umd/react.production.min.js"></script>
<script defer onload="__cdnImportAsyncHandler('lottie')" onerror="__cdnImportAsyncHandler('lottie', true)" src="https://cdn.jsdelivr.net/npm/[email protected]/build/player/lottie.min.js"></script>
<script src="https://cdn.jsdelivr.net/npm/[email protected]/dist/axios.min.js"></script>Input file
By default, every module that defined in plugin config will generate its <script> tag into the output file, no matter this module was used in the project or not.
But now you can set attribute data-cdn-import in <meta> tag of the input file, to determind which module should generate <script> into the output file.
For example (example/react/index.html):
<!DOCTYPE html>
<html lang="en">
<head>
<meta charset="UTF-8" data-cdn-import="React,lottie" />
<meta name="viewport" content="width=device-width, initial-scale=1.0" />
<title>Example</title>
</head>
<body>
<div id="root"></div>
<script type="module" src="/src/main.tsx"></script>
</body>
</html>According to data-cdn-import="React,lottie", plugin will only handle React and lottie modules and generate their <script> into the output file (example/react/dist/index.html):
<!DOCTYPE html>
<html lang="en">
<head>
<meta charset="UTF-8" />
<meta name="viewport" content="width=device-width, initial-scale=1.0" />
<title>Example</title>
<script>window.__cdnImportAsync_varToNameMap={"React":"react","lottie":"lottie-web"};</script>
<script>function __cdnImportAsyncHandler(o,n){n&&window.cdnImportAsync_loadingErrorModules.push(o);var d=new CustomEvent("asyncmoduleloaded",{detail:{module:o,isError:!!n}});window.dispatchEvent(d)}window.cdnImportAsync_loadingErrorModules=window.cdnImportAsync_loadingErrorModules||[];</script>
<script async onload="__cdnImportAsyncHandler('React')" onerror="__cdnImportAsyncHandler('React', true)" src="https://cdn.jsdelivr.net/npm/[email protected]/umd/react.production.min.js"></script>
<script defer onload="__cdnImportAsyncHandler('lottie')" onerror="__cdnImportAsyncHandler('lottie', true)" src="https://cdn.jsdelivr.net/npm/[email protected]/build/player/lottie.min.js"></script>
<script type="module" crossorigin src="/assets/index.c9473e27.js"></script>
<link rel="stylesheet" href="/assets/index.cd9c0392.css">
</head>
<body>
<div id="root"></div>
</body>
</html>Mode suffix
Using suffix @async or @defer within data-cdn-import can also generate asynchronous <script> tag of marked module.
Example
Notice that here's no mode: 'async' in the configs of React module:
// vite.config.js
import cdnImport from 'vite-plugin-cdn-import-async'
export default {
plugins: [
cdnImport({
modules: [
{
name: 'react',
var: 'React',
path: `https://cdn.jsdelivr.net/npm/[email protected]/umd/react.production.min.js`,
},
{
name: 'lottie-web',
var: 'lottie',
mode: 'defer',
path: `https://cdn.jsdelivr.net/npm/[email protected]/build/player/lottie.min.js`,
},
{
name: 'axios',
var: 'axios',
path: 'https://cdn.jsdelivr.net/npm/[email protected]/dist/axios.min.js',
}
],
}),
],
}And the input file (example/react/index.html) likes:
<!DOCTYPE html>
<html lang="en">
<head>
<meta charset="UTF-8" data-cdn-import="React@async,lottie" />
<meta name="viewport" content="width=device-width, initial-scale=1.0" />
<title>Example</title>
</head>
<body>
<div id="root"></div>
<script type="module" src="/src/main.tsx"></script>
</body>
</html>According to React@async within data-cdn-import, the React module will generate <script> tag with async attribute into the output file (example/react/dist/index.html):
<!DOCTYPE html>
<html lang="en">
<head>
<meta charset="UTF-8" />
<meta name="viewport" content="width=device-width, initial-scale=1.0" />
<title>Example</title>
<script>window.__cdnImportAsync_nameToVar={"react":"React","lottie-web":"lottie"};</script>
<script>function __cdnImportAsyncHandler(o,n){n&&window.cdnImportAsync_loadingErrorModules.push(o);var d=new CustomEvent("asyncmoduleloaded",{detail:{module:o,isError:!!n}});window.dispatchEvent(d)}window.cdnImportAsync_loadingErrorModules=window.cdnImportAsync_loadingErrorModules||[];</script>
<script async onload="__cdnImportAsyncHandler('React')" onerror="__cdnImportAsyncHandler('React', true)" src="https://cdn.jsdelivr.net/npm/[email protected]/umd/react.production.min.js"></script>
<script defer onload="__cdnImportAsyncHandler('lottie')" onerror="__cdnImportAsyncHandler('lottie', true)" src="https://cdn.jsdelivr.net/npm/[email protected]/build/player/lottie.min.js"></script>
<script type="module" crossorigin src="/assets/index.c9473e27.js"></script>
<link rel="stylesheet" href="/assets/index.cd9c0392.css">
</head>
<body>
<div id="root"></div>
</body>
</html>Lazy loading
In addition to async or defer as the value of mode, here's other avalable values for lazy-loading:
| Value of mode | Description |
| ---- | ---- |
| DOMContentLoaded | Module will start being loaded within DOMContentLoaded event of window. |
| load | Module will start being loaded within load event of window. |
| [milliseconds] | Module will start being loaded in specified milliseconds after load event emits. |
Example
In vite.config.js:
export default defineConfig({
plugins: [
importToCDN({
modules: [
{
name: 'react',
var: 'React',
mode: 'DOMContentLoaded',
path: `https://cdn.jsdelivr.net/npm/[email protected]/umd/react.production.min.js`,
},
{
name: 'lottie-web',
var: 'lottie',
mode: '3000',
path: `https://cdn.jsdelivr.net/npm/[email protected]/build/player/lottie.min.js`,
},
{
name: 'axios',
var: 'axios',
mode: 'load',
path: 'https://cdn.jsdelivr.net/npm/[email protected]/dist/axios.min.js',
}
],
}),
reactRefresh(),
],
})Or the entry file:
<meta data-cdn-import="React@DOMContentLoaded,lottie@3000,axios@load" />The output file would be like:
<script>window.__cdnImportAsync_nameToVar={"react":"React","lottie-web":"lottie"};</script>
<script>function __cdnImportAsyncHandler(o,n){n&&window.cdnImportAsync_loadingErrorModules.push(o);var d=new CustomEvent("asyncmoduleloaded",{detail:{module:o,isError:!!n}});window.dispatchEvent(d)}window.cdnImportAsync_loadingErrorModules=window.cdnImportAsync_loadingErrorModules||[];</script>
<script>function __cdnImportAsync_deferredLoader(n,r){var c=document.createElement("script");c.onload=function(){__cdnImportAsyncHandler(n)},c.onerror=function(){__cdnImportAsyncHandler(n,!0)},c.src=r,document.body.appendChild(c)}</script>
<script>!function(){window.addEventListener("DOMContentLoaded",function e(){__cdnImportAsync_deferredLoader("React","https://cdn.jsdelivr.net/npm/[email protected]/umd/react.production.min.js"),window.removeEventListener("DOMContentLoaded",e)},!1)}();</script>
<script>!function(){window.addEventListener("load",function e(){setTimeout(function(){__cdnImportAsync_deferredLoader("lottie","https://cdn.jsdelivr.net/npm/[email protected]/build/player/lottie.min.js")},3000),window.removeEventListener("load",e)},!1)}();</script>
<script>!function(){window.addEventListener("load",function e(){__cdnImportAsync_deferredLoader("axios","https://cdn.jsdelivr.net/npm/[email protected]/dist/axios.min.js"),window.removeEventListener("load",e)},!1)}();</script>
Import async module
Once a module is loaded asynchronously by mode config, you should create an function to handle it while using it in pages:
export function cdnAsyncImport(moduleName: string, isDev: boolean): Promise<any> {
if (isDev) {
return Promise.reject()
}
return new Promise((resolve, rejects) => {
const errorModules = window.cdnImportAsync_loadingErrorModules || []
const moduleVar = window.__cdnImportAsync_nameToVar[moduleName]
if (errorModules.includes(moduleVar)) {
rejects()
} else if (window[moduleVar]) {
resolve(window[moduleVar])
} else {
window.addEventListener(
'asyncmoduleloaded',
(e: any) => {
const { detail } = e || {}
if (detail && !detail.isError && window[moduleVar]) {
resolve(window[moduleVar])
} else {
rejects()
}
},
false
)
}
})
}
cdnAsyncImport('lottie-web', import.meta.env.DEV).then(lottie => {
// Async module has been successfully loaded.
console.log(lottie)
}).catch(() => {
// Handling DEV or Error case
import('lottie-web').then(...)
})Other ussages
Other basic ussages see vite-plugin-cdn-import.