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https://github.com/mbrevda/react-image
React.js <img> tag rendering with multiple fallback & loader support
https://github.com/mbrevda/react-image
fallback image loader preload preloader react react-img-multi reactjs
Last synced: about 2 months ago
JSON representation
React.js <img> tag rendering with multiple fallback & loader support
- Host: GitHub
- URL: https://github.com/mbrevda/react-image
- Owner: mbrevda
- License: mit
- Created: 2016-10-28T10:22:26.000Z (almost 8 years ago)
- Default Branch: master
- Last Pushed: 2024-04-13T18:43:29.000Z (5 months ago)
- Last Synced: 2024-04-14T08:01:30.728Z (5 months ago)
- Topics: fallback, image, loader, preload, preloader, react, react-img-multi, reactjs
- Language: TypeScript
- Size: 6.91 MB
- Stars: 1,162
- Watchers: 6
- Forks: 88
- Open Issues: 6
-
Metadata Files:
- Readme: README.md
- Changelog: CHANGELOG.md
- Contributing: CONTRIBUTING.md
- License: LICENSE
Awesome Lists containing this project
README
# React Image 🏝 🏖 🏜
[](https://www.npmjs.com/package/react-image)
[](https://www.npmjs.com/package/react-image)
[](https://www.npmjs.com/package/react-image)
[](https://www.npmjs.com/package/react-image)
[](https://snyk.io/test/github/mbrevda/react-image)
**React Image** is an `![]()
` tag replacement and hook for [React.js](https://facebook.github.io/react/), supporting fallback to alternate sources when loading an image fails.
**React Image** allows one or more images to be used as fallback images in the event that the browser couldn't load the previous image. When using the component, you can specify any React element to be used before an image is loaded (i.e. a spinner) or in the event that the specified image(s) could not be loaded. When using the hook this can be achieved by wrapping the component with [``](https://reactjs.org/docs/react-api.html#reactsuspense) and specifying the `fallback` prop.
**React Image** uses the `useImage` hook internally which encapsulates all the image loading logic. This hook works with React Suspense by default and will suspend painting until the image is downloaded and decoded by the browser.
## Getting started
1. To include the code locally in ES6, CommonJS, or UMD format, install `react-image` using npm:
```
npm install react-image --save
```
2. To include the code globally from a cdn:
```html
```
## Dependencies
`react-image` has no external dependencies, aside from a version of `react` and `react-dom` which support hooks and `@babel/runtime`.
## Documentation
You can use the standalone component, documented below, or the `useImage` hook.
### useImage():
The `useImage` hook allows for incorporating `react-image`'s logic in any component. When using the hook, the component can be wrapped in `` to keep it from rendering until the image is ready. Specify the `fallback` prop to show a spinner or any other component to the user while the browser is loading. The hook will throw an error if it fails to find any images. You can wrap your component with an [Error Boundary](https://reactjs.org/docs/code-splitting.html#error-boundaries) to catch this scenario and do/show something.
Example usage:
```js
import React, {Suspense} from 'react'
import {useImage} from 'react-image'
function MyImageComponent() {
const {src} = useImage({
srcList: 'https://www.example.com/foo.jpg',
})
return 
}
export default function MyComponent() {
return (
)
}
```
### `useImage` API:
- `srcList`: a string or array of strings. `useImage` will try loading these one at a time and returns after the first one is successfully loaded
- `imgPromise`: a promise that accepts a url and returns a promise which resolves if the image is successfully loaded or rejects if the image doesn't load. You can inject an alternative implementation for advanced custom behaviour such as logging errors or dealing with servers that return an image with a 404 header
- `useSuspense`: boolean. By default, `useImage` will tell React to suspend rendering until an image is downloaded. Suspense can be disabled by setting this to false.
**returns:**
- `src`: the resolved image address
- `isLoading`: the currently loading status. Note: this is never true when using Suspense
- `error`: any errors ecountered, if any
### Standalone component (legacy)
When possible, you should use the `useImage` hook. This provides for greater flexibility and provides support for React Suspense.
Include `react-image` in your component:
```js
import {Img} from 'react-image'
```
and set a source for the image:
```js
const myComponent = () => 
```
will resolve to:
```js
```
If the image cannot be loaded, **`![]()
` 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.
```js
const myComponent = () => (
)
```
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:
```js
const myComponent = () => (
)
```
If an image was previously loaded successfully (since the last time the page was loaded), the loader will not be shown and the image will be rendered immediately instead.
### Show a fallback element if none of the images could be loaded:
```js
const myComponent = () => (
)
```
### NOTE:
The following options only apply to the `![]()
` component, not to the `useImage` hook. When using the hook you can inject a custom image resolver with custom behaviour as required.
### Decode before paint
By default and when supported by the browser, `react-image` uses [`Image.decode()`](https://html.spec.whatwg.org/multipage/embedded-content.html#dom-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`:
```js
const myComponent = () => (
)
```
### Loading images with a CORS policy
When loading images from another domain with a [CORS policy](https://developer.mozilla.org/en-US/docs/Web/HTML/CORS_settings_attributes), you may find you need to use the `crossorigin` attribute. For example:
```js
const myComponent = () => (
)
```
### 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 `![]()
` or the loaders).
For example, to animate the display of the image (and animate out the loader) a wrapper can be set:
```js
{
return
{children}
}}
/>
```
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 right away. 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`](https://www.npmjs.com/package/react-visibility-sensor). Here is a quick sample (psudocode/untested!):
```js
import {Img} from 'react-image'
import VisibilitySensor from 'react-visibility-sensor'
const myComponent = () =>
```
Note: it is not necessary to use **React Image** to prevent loading of images past "the fold" (i.e. not currently visible in the window). Instead just use the native HTML `![]()
` element and the `loading="lazy"` prop. See more [here](https://addyosmani.com/blog/lazy-loading/).
### Animate image loading
see above
## License
`react-image` is available under the MIT License