Huge News!Announcing our $40M Series B led by Abstract Ventures.Learn More →

github.com/iconfu/svg-inject

Package Overview

Dependencies

Alerts

File Explorer

Install Socket

Detect and block malicious and high-risk dependencies

Install

github.com/iconfu/svg-inject

v1.2.3
Source
Go

Version published: 6 years ago

Created: 6 years ago

Source

minified size gzip size

SVGInject

A tiny, intuitive, robust, caching solution for injecting SVG files inline into the DOM.

Developed and maintained by INCORS, the creators of iconfu.com.

What does it do?

SVGInject replaces an <img> element with an inline SVG. The SVG is loaded from the URL specified in the src attribute of the <img> element.

SVG Injection

Element before injection:

<img src="image.svg" onload="SVGInject(this)" />

Element after injection (SVG loaded from image.svg):

<svg version="1.1" ...> ... </svg>

Why should I use it?

An SVG can only be properly styled with CSS and accessed with Javascript on element level if the SVG is inline in the DOM. With SVGInject you can keep your SVGs as individual files, but still access them with CSS and Javascript.

How to install SVGInject?

Manually

Include the SVGInject Javascript file in the <head> element of the HTML document, or anywhere before the first usage of SVGInject

<head>
  ...
  <script src="svg-inject.min.js"></script>
  ...
</head>

Download plain version (v1.2.3): svg-inject.js

Download minified version (v1.2.3): svg-inject.min.js

npm

If you are using npm

$ npm install @iconfu/svg-inject

Yarn

If you are using Yarn

$ yarn add @iconfu/svg-inject

Basic usage

Option 1 - Call SVGInject from the `onload` attribute

Add onload="SVGInject(this)" to any <img> element where you want the SVG to be injected.

For most use cases this approach is recommended and provides nice advantages.

<html>
<head>
  <script src="svg-inject.min.js"></script>
</head>
<body>
  <img src="image1.svg" onload="SVGInject(this)" />
  <img src="image2.svg" onload="SVGInject(this)" />
</body>
</html>

Option 2 - Call SVGInject from anywhere

<html>
<body>
  <img src="image1.svg" class="injectable" />
  <img src="image2.svg" class="injectable" />

  <script src="svg-inject.min.js"></script>
  <script>
    SVGInject(document.querySelector("img.injectable"));
  </script>
</body>
</html>

Hooray :tada: - The SVGs get injected and are styleable!!!

What are the advantages?

Wide browser support: Works on all browsers supporting SVG. Yes, this includes Internet Explorer 9 and higher! (full list)
Fallback without Javascript: If Javascript is not available the SVG will still show. It's just not styleable with CSS.
Fallback if image source is not available: Behaves like a normal <img> element if file not found or not available.
Prevention of ID conflicts: IDs in the SVG are made unique before injection to prevent ID conflicts in the DOM.

What are additional advantages when using `onload`?

The recommended way to trigger injection is to call SVGInject(this) inside the onload attribute:

<img ... onload="SVGInject(this)" />

This provides additional advantages:

Intuitive usage: Insert SVG images into HTML code just as PNG images, with only one additional instruction. It's very clear to understand what it does by looking at the pure HTML.
Works with dynamic content: If <img> elements are added dynamically, injection still works.
Built-in prevention of unstyled image flash: SVGInject hides <img> elements until injection is complete, thus preventing a brief flicker of the unstyled image (called unstyled image flash).
Early injection: The injection can already start before the DOM content is fully loaded.
Standard-conform: The onload event handler on <img> elements has long been supported by all browsers and is officially part of the W3C specification since HTML5.0.

If you do not want to use the onload attribute but prefer to inject SVGs directly from Javascript, you can find more information here.

What are the limitations?

SVGInject is intended to work in production environments however it has a few limitations you should be aware of:

The image source must conform to the same-origin policy, which basically means the image origin must be where the website is running. This may be bypassed using the Cross-Origin Resource Sharing (CORS) mechanism.
Due to the same-origin policy SVGInject does not work when run from the local file system in many browsers (Chrome, Safari), yet in Firefox it works.

How are attributes handled?

All attributes are copied from the <img> element to the injected <svg> element before injection with the following exceptions:

The src, title, alt, onerror and onload attributes are not copied
The title attribute is transformed to a <title> element and inserted as the first child element of the injeted SVG. If there is an existing <title> element as first child element it gets replaced.

You can disable the previously described attribute handling by setting the copyAttributes option to false. You may also implement your own attribute handling in the beforeInject options hook.

Additionally, after loading the SVG, the value of the src attribute of the <img> element is transformed to an absolute URL and inserted as a data-inject-url attribute.

API

Function	Description
SVGInject(img, options)	Injects the SVG specified in the `src` attribute of the specified `img` element or array of elements. The optional second parameter sets the options for this injection. Returns a `Promise` object which resolves if all passed in `img` elements have either been injected or failed to inject (Only if a global Promise object is available like in all modern browsers or through a Promise Polyfill).
SVGInject.setOptions(options)	Sets the default options for SVGInject.
SVGInject.err(img, fallbackSrc)	Used in `onerror` event of an `<img>` element to handle cases when loading of the original source fails (for example if the file is corrupt or not found or if the browser does not support SVG). This triggers a call to the option's `onFail` hook if available. The optional second parameter will be set as the new `src` attribute for the `img` element.

Options

Property name	Type	Default	Description
useCache	boolean	`true`	If set to `true` the SVG will be cached using the absolute URL. The cache only persists for the lifetime of the page. Without caching images with the same absolute URL will trigger a new XMLHttpRequest but browser caching will still apply.
copyAttributes	boolean	`true`	If set to `true` attributes will be copied from the `img` to the injected `svg` element. You may implement your own method for copying attributes in the `beforeInject` options hook.
makeIdsUnique	boolean	`true`	If set to `true` all IDs of elements in the SVG are made unique by appending the string "--inject-X", where X is a running number which increases with each injection. This is done to avoid duplicate IDs in the DOM. If set to `false`, all IDs within the SVG will be preserved.
beforeLoad	function(img)	`undefined`	Hook before SVG is loaded. The `img` element is passed as a parameter. If the hook returns a string it is used as the URL instead of the `img` element's `src` attribute.
afterLoad	function(svg, svgString)	`undefined`	Hook after SVG is loaded. The loaded `svg` element and `svgString` string are passed as a parameters. If caching is active this hook will only get called once for injected SVGs with the same absolute path. Changes to the `svg` element in this hook will be applied to all injected SVGs with the same absolute path. It's also possible to return an new SVG string or SVG element which will then be used for later injections.
beforeInject	function(img, svg)	`undefined`	Hook directly before the SVG is injected. The `img` and `svg` elements are passed as parameters. The hook is called for every injected SVG. If an Element is returned it gets injected instead of applying the default SVG injection.
afterInject	function(img, svg)	`undefined`	Hook after SVG is injected. The `img` and `svg` elements are passed as parameters.
onAllFinish	function()	`undefined`	Hook after all `img` elements passed to an SVGInject() call have either been injected or failed to inject.
onFail	function(img, status)	`undefined`	Hook after injection fails. The `img` element and a `status` string are passed as an parameter. The `status` has one of the values: `'SVG_NOT_SUPPORTED'` - the browser does not support SVG, `'SVG_INVALID'` - the SVG is not in a valid format or `'LOAD_FAIL'` - loading of the SVG failed. If SVGInject is used with the `onload` attribute, `onerror="SVGinject.err(this)"` must be added to the `<img>` element to make sure `onFail` is called.

How does SVGInject prevent "unstyled image flash"

Before an SVG is injected the original unstyled SVG may be displayed for a brief moment by the browser. If a style is already applied to the SVG at runtime, the styled SVG will look different from the unstyled SVG, causing a brief “flashing” of the unstyled SVG before injection occurs. We call this effect unstyled image flash.

If SVGInject is used with the onload attribute, SVGInject has a built-in functionality to prevent unstyled image flash. A <style> element with one CSS rule is added to the document to hide all injectable <img> elements until injection is complete.

When using Javascript directly SVGInject has no build in functionality to prevent unstyled image flash. You can find a custom solution for this in the example for using SVGInject without the onload attribute.

How to use SVGInject directly from Javascript?

Instead of using the onload attribute on the <img> element you can also call SVGInject directly from Javascript.

Examples:

// inject by class name
SVGInject(document.getElementsByClassName('myClassName'));

// inject by id
SVGInject(document.getElementById('myId'));

You need to make sure the images are already inside the DOM before injection like this:

document.addEventListener('DOMContentLoaded', function() {
  // call SVGInject() from here
});

If you dynamically insert new <img> elements you need to call SVGInject() on these elements after their insertion.

Fallback for old browsers

If the browser does not support SVG (IE8 and IE7), this simple fallback solution replaces the src attribute with an alternative image URL.

<img src="image.svg" onload="SVGInject(this)" onerror="SVGInject.err(this, 'image.png')" />

More detailed information on implementing fallback solutions for old browsers can be found on our Fallback solutions WIki page.

What about some examples?

Here are some examples which cover the most common use cases.

Basic Example

This is the standard usage of SVGInject which works on all modern browsers, and IE9+.

<html>
<head>
  <script src="svg-inject.min.js"></script>
</head>
<body>
  <img src="image1.svg" onload="SVGInject(this)" />
  <img src="image2.svg" onload="SVGInject(this)" />
</body>
</html>

Example using `options`

This example shows how to use SVGInject with multiple options.

<html>
<head>
  <script src="svg-inject.min.js"></script>

  <script>
    SVGInject.setOptions({
      useCache: false, // no caching
      copyAttributes: false, // do not copy attributes from `<img>` to `<svg>`
      makeIdsUnique: false, // do not make ids used within the SVG unique
      afterLoad: function(svg, svgString) {
        // add a class to the svg
        svg.classList.add('my-class');
      },
      beforeInject: function(img, svg) {
        // wrap SVG in a div element
        var div = document.createElement('div');
        div.appendChild(svg);
        return div;
      },
      afterInject: function(img, svg) {
        // set opacity
        svg.style.opacity = 1;
      },
      onFail: function(img) {
        // set the image background red
        img.style.background = 'red';
      }
    });
  </script>
</head>
<body>
  <img src="image.svg" onload="SVGInject(this)" onerror="SVGInject.err(this)" />
</body>
</html>

Example without using the `onload` attribute

This example shows how to use SVGInject directly from Javascript without the onload attribute. After the DOM content has loaded, SVGInject is called on all elements with class injectable. It also implements a method to prevent unstyled image flash.

<html>
<head>
  <script src="svg-inject.min.js"></script>

  <!-- hide images until injection has completed or failed -->
  <style>
    /* hide all img elements until the svg is injected to prevent "unstyled image flash" */
    img.injectable {
      visibility: hidden;
    }
  </style>

  <script>
    SVGInject.setOptions({
      onFail: function(img, svg) {
        // if injection fails show the img element
        img.classList.remove('injectable');
      }
    });

    document.addEventListener('DOMContentLoaded', function() {
      // inject images with an .svg file ending
      SVGInject(document.querySelectorAll('img.injectable'), {
        onAllFinish: function() {
          // the SVG injection has finished for all three images

        }
      });
    });
  </script>
</head>
<body>
  <img src="image_1.svg" class="injectable" />
  <img src="image_2.svg" class="injectable" />
  <img src="image_3.svg" class="injectable" />
</body>
</html>

Browser support

Full support for all modern browsers, and IE9+ (full list)

Support for legacy browsers with optional PNG fallback method

License

MIT License

FAQs

What is github.com/iconfu/svg-inject?

Package last updated on 12 Mar 2019

Did you know?

Socket for GitHub automatically highlights issues in each pull request and monitors the health of all your open source dependencies. Discover the contents of your packages and block harmful activity before you install or update your dependencies.

Install

github.com/iconfu/svg-inject

SVGInject

What does it do?

Why should I use it?

How to install SVGInject?

Manually

npm

Yarn

Basic usage

Option 1 - Call SVGInject from the onload attribute

Option 2 - Call SVGInject from anywhere

What are the advantages?

What are additional advantages when using onload?

What are the limitations?

How are attributes handled?

API

Options

How does SVGInject prevent "unstyled image flash"

How to use SVGInject directly from Javascript?

Fallback for old browsers

What about some examples?

Basic Example

Example using options

Example without using the onload attribute

Browser support

License

Related posts

Typosquatting Cryptographic Libraries: Malicious npm Packages Threaten Crypto Developers with Keylogging and Wallet Theft

Weekly Downloads Now Available in npm Package Search Results

Option 1 - Call SVGInject from the `onload` attribute

What are additional advantages when using `onload`?

Example using `options`

Example without using the `onload` attribute