react-image-fork
v2.1.12
Published
React Image is an <img> tag replacement for react, featuring preloader and multiple image fallback support
Downloads
24
Maintainers
Readme
React Image 🏝 🏖 🏜
React Image is an <img>
tag replacement for React.js, featuring preloader and multiple image fallback support.
With React Image you can specify multiple images to be used as fallbacks in the event that the browser couldn't load the previous image. Additionally, you can specify any React element to be used before an image is loaded (i.e. a spinner) and in the event than the specified image(s) could not be loaded.
React Image will cleverly hide "broken" images to prevent showing the browsers default "broken image" placeholder. React Image caches past attempts to load an image so that the same image won't be attempted to be pulled over the network again, until the next page reload.
On unmount React Image will abort any current image downloads potentially saving bandwidth and browser resources should the image no longer be desirable.
This package was formerly known as react-img-multi
. Special thanks to @yuanyan for agreeing to relinquish the name!
Getting started
- To include the code locally in ES6, CommonJS, or UMD format, install
react-image
using npm:
npm install react-image --save
- To include the code globally from a cdn:
<script src="https://unpkg.com/react-image/umd/index.js"></script>
Dependencies
react-image
has no external dependencies, aside for the usual react
and react-dom
.
Documentation
Include react-image
in your component:
// using an ES6 transpiler, like babel
import Img from 'react-image'
// otherwise
let Img = require('react-image')
and set a source for the image:
const myComponent = () => <Img src="https://www.example.com/foo.jpg" />
will generate:
<img src="https://www.example.com/foo.jpg">
If the image cannot be loaded, <img>
will not be rendered, preventing a "broken" image from showing.
Multiple fallback images:
When src
is specified as an array, react-image
will attempt to load all the images specified in the array, starting at the first and continuing until an image has been successfully loaded.
const myComponent = () => (
<Img
src={['https://www.example.com/foo.jpg', 'https://www.example.com/bar.jpg']}
/>
)
If an image has previously been attempted unsuccessfully, react-image
will not retry loading it again until the page is reloaded.
Show a "spinner" or other element before the image is loaded:
const myComponent = () =>
<Img
src={[
'https://www.example.com/foo.jpg',
'https://www.example.com/bar.jpg'
]}
loader={/*any valid react element */}
/>
If an image was previously loaded successfully (since the last time this page was loaded), the loader will not be shown and the image will be rendered directly instead.
Show a fallback element if none of the images could be loaded:
const myComponent = () =>
<Img
src={[
'https://www.example.com/foo.jpg',
'https://www.example.com/bar.jpg'
]}
unloader={/*any valid react element */}
/>
Decoding before paint
By default and when supported by the browser, react-image
uses img.decode()
to decode the image and only render it when it's fully ready to be painted. While this doesn't matter much for vector images (such as svg's) which are rendered immediately, decoding the image before painting prevents the browser from hanging or flashing while the image is decoded. If this behaviour is undesirable, it can be disabled by setting the decode
prop to false
:
const myComponent = () => (
<Img src={'https://www.example.com/foo.jpg'} decode={false} />
)
Loading images with a CORS policy
When loading images from another domain with a CORS policy, you may find you need to use the crossorigin
attribute. For example:
const myComponent = () => (
<Img src={'https://www.example.com/foo.jpg'} crossorigin="anonymous" />
)
Animations and other advanced uses
A wrapper element container
can be used to facilitate higher level operations which are beyond the scope of this project. container
takes a single property, children
which is whatever is passed in by React Image (i.e. the final <img>
or the loaders).
For example, to animate the display of the image (and animate out the loader) a wrapper can be set:
<Img
src={'https://www.example.com/foo.jpg'}
container={children => {
return <div className="foo">{children}</div>
}}
/>
The <img>
will now be contained by the div
with class foo
which can be targeted via css.
A crude example of a transition using ReactCSSTransitionReplace can be found here. Error reporting (i.e. logging images that loaded ok or failed to load) can be accomplished with container
, too.
A sample implementation can be found here.
By default, the loader and unloader components will also be wrapped by the container
component. These can be set independently by passing a container via loaderContainer
or unloaderContainer
. To disable the loader or unloader from being wrapped, pass a noop to loaderContainer
or unloaderContainer
(like unloaderContainer={img => img}
).
Recipes
Delay rendering until element is visible (lazy rendering)
By definition, React Image will try loading images as soon as the <Img>
element is rendered in the DOM. This may be undesirable in some situations, such as when the page has many images. As with any react element, rendering can be delayed until the image is actually visible in the viewport using popular libraries such as react-visibility-sensor
. Here is a quick sample (untested!):
import Img from 'react-image'
import VisibilitySensor from 'react-visibility-sensor'
const myComponent = () =>
<VisibilitySensor>
<Img src='https://www.example.com/foo.jpg'>
</VisibilitySensor>
Animate image loading
see above
Browser Support
react-image
does not include an Object.assign
polyfill, that may be needed depending on your targeted browsers. You can add it in one of the following ways:
include it in your package:
https://www.npmjs.com/package/es6-object-assign
Use Mozilla's polyfill: https://developer.mozilla.org/en/docs/Web/JavaScript/Reference/Global_Objects/Object/assign#Polyfill
Include the following code before including
react-image
:
Object.assign = Object.assign ||
function(r) {
for (var t = 1; t < arguments.length; t++) {
var n = arguments[t]
for (var a in n)
Object.prototype.hasOwnProperty.call(n, a) && (r[a] = n[a])
}
return r
}
License
react-image
is available under the MIT License