external-svg-loader
v1.7.1
Published
Plug 'n play external SVG loader
Downloads
76,668
Readme
SVG Loader
SVGs from an external source can be rendered with <img>
tags, but this has multiple drawbacks: you can't customize the fill or stroke colors, use CSS variables, or use focus/hover states.
SVG Loader is a simple JS library that fetches SVGs using XHR and injects the SVG code in the tag's place. This lets you use externally stored SVGs (e.g, on CDN) just like inline SVGs.
It's super-tiny, works with all frameworks, requires no additional code except the initial script load, and has minimal to no impact on performance.
How to Use?
SVG Loader is designed to be plug and play. Hence, all you need to is to include the loader JS anywhere in your code, and then start using the code like this:
Download and Include
<!--
Include this script anywhere in your code, preferably <HEAD> so
icons can be fetched faster.
-->
<script type="text/javascript" src="svg-loader.min.js" async></script>
<!-- Use an external SVG -->
<svg
data-src="https://unpkg.com/@mdi/[email protected]/svg/star.svg"
width="50"
height="50"
fill="red"></svg>
<svg
data-src="https://unpkg.com/@mdi/[email protected]/svg/heart.svg"
width="50"
height="50"
fill="red"></svg>
<svg
data-src="https://unpkg.com/@mdi/[email protected]/svg/cog.svg"
width="50"
height="50"
fill="currentColor"
style="color: purple;"></svg>
Note: Because SVG Loader fetches file using XHRs, it's limited by CORS policies of the browser.
So you need to ensure that correct Access-Control-Allow-Origin
headers are sent with the file being served or that the files are hosted on your own domain.
Or, use from the npm package
The library is framework/platform agnostic. You should be able to use it in React, Vue.js and others as long as you're using the correct attributes.
npm install external-svg-loader
Then, in your app, require/import external-svg-loader
anywhere. Here's an example:
import React from "react";
import ReactDOM from "react-dom";
import "external-svg-loader";
class App extends React.Component {
render() {
return (
<svg
data-src="https://s2.svgbox.net/materialui.svg?ic=mail"
fill="currentColor"
width="50px"
height="50px"
style={{
color: "red"
}}
/>
);
}
}
ReactDOM.render(<App />, document.getElementById("container"));
Or, use a CDN
SVG loader can also be included via unpkg CDN. Example:
<script
type="text/javascript"
src="https://unpkg.com/external-svg-loader@latest/svg-loader.min.js"
async></script>
Configuration
1. Disable/Modify Caching
By default, the XHR response is cached for 30 days, so that any subsequent loads are instantenous. You can disable this behavior by passing data-cache="disabled"
.
You can destroy the currently stored cache by calling:
SVGLoader.destroyCache();
You can also modify the caching period by passing number of seconds. Example:
Cache for a week
<svg
data-src="https://unpkg.com/@mdi/[email protected]/svg/heart.svg"
data-cache="604800"
width="50"
height="50"></svg>
Cache for a six hours
<svg
data-src="https://unpkg.com/@mdi/[email protected]/svg/heart.svg"
data-cache="21600"
width="50"
height="50"></svg>
Disable Caching
<svg
data-src="https://unpkg.com/@mdi/[email protected]/svg/heart.svg"
data-cache="disabled"
width="50"
height="50"></svg>
2. Enable Javascript
SVG format supports scripting. However, for security reasons, svg-loader will strip all JS code before injecting the SVG file. You can enable it by:
<svg
data-src="https://unpkg.com/@mdi/[email protected]/svg/heart.svg"
data-js="enabled"
onclick="alert('clicked')"
width="50"
height="50"
fill="red"></svg>
3. Disable Unique IDs, Styling
To prevent conflicts between conflicting identifiers of different SVGs, svg-loader scopes the identifiers and styling rules by adding prefixes.
You can disable this behavior by:
Disable Unique IDs
<svg
data-src="https://unpkg.com/@mdi/[email protected]/svg/heart.svg"
data-unique-ids="disabled"
width="50"
height="50"
fill="red"></svg>
Disable CSS Scoping
<svg
data-src="https://unpkg.com/@mdi/[email protected]/svg/heart.svg"
data-css-scoping="disabled"
width="50"
height="50"
fill="red"></svg>
Lazy Loading
You can also lazy load icons by using data-loading=lazy
. This will make icon not load until it's about to enter the viewport. For lazy loading, external-svg-loader
uses Intersection Observer API.
<svg
data-src="https://unpkg.com/@mdi/[email protected]/svg/heart.svg"
data-loading="lazy"
width="50"
height="50"></svg>
Event
When the SVG has been loaded an event iconload
is triggered. This can be used to get the references to the loaded SVG element and do some further processing. You can also use the oniconload
inline function.
Using oniconload
inline function
<svg
data-src="https://unpkg.com/@mdi/[email protected]/svg/cog.svg"
oniconload="console.log('Icon loaded', this)"></svg>
Using addEventListener
<svg data-src="https://unpkg.com/@mdi/[email protected]/svg/cog.svg"></svg>
<script>
window.addEventListener('iconload', (e) => {
if (e.target.id === 'iconload') {
console.log('Icon loaded', e.target);
}
});
</script>
Using the iconloaderror
event
When an error occurs during loading of the SVG file, an iconloaderror
event is triggered, passing the error message as the event's detail
.
<svg data-src="https://unpkg.com/@mdi/[email protected]/svg/this-svg-does-not-exist.svg"></svg>
<script>
window.addEventListener('iconloaderror', (e) => {
console.error('Failed to load SVG:', e.detail);
});
</script>
Similarly to the iconload
event, iconloaderror
can also be used with an inline function, which will have access to an error
argument (the Error
object that was thrown):
<svg
data-src="https://unpkg.com/@mdi/[email protected]/svg/cog.svg"
oniconloaderror="console.log('Error loading SVG:', error.toString())"></svg>
Using Events in React
React doesn't support custom events out of the box. To circumvent this limitation, you can use refs.
class MyApp extends React.Component {
constructor(props) {
super(props);
this.ref = React.createRef()
}
render() {
return (<svg data-src="https://unpkg.com/@mdi/[email protected]/svg/cog.svg" ref={this.ref}></svg>);
}
componentDidMount() {
this.ref.current.addEventListener('iconload', () => {
console.log("Icon Loaded", this.ref.current)
});
this.ref.current.addEventListener('iconloaderror', (e) => {
console.error('Failed to load SVG:', e.detail);
});
}
}
LICENSE
MIT