react-collapse 



Component-wrapper for collapse animation for elements with variable (and dynamic) height

!React Collapse

Demo

http://nkbt.github.io/react-collapse

Codepen demo

http://codepen.io/nkbt/pen/MarzEg

Installation

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``sh
npm install --save react-collapse
`

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`sh
yarn add react-collapse
`

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`html


(Module exposed as ReactCollapse)
`

Usage

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`js
import {Collapse} from 'react-collapse';

// ...





`

---

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Use Unmount component provided as:

`js
import {UnmountClosed} from 'react-collapse';

// ...





`

Example example/App/AutoUnmount.js

---

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If you want a controlled and accessible implementation, check out this example

Options

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Expands or collapses content.

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One or multiple children with static, variable or dynamic height.

`js



Paragraph of text

Another paragraph is also OK

Images and any other content are ok too

`

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It is possible to set className for extra div elements that ReactCollapse creates.

Example:
`js





`

Default values:
`js
const theme = {
collapse: 'ReactCollapse--collapse',
content: 'ReactCollapse--content'
}
`

Which ends up in the following markup:
`html



`

IMPORTANT: these are not style objects, but class names!

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Callback functions, triggered when animation has completed (onRest) or has just started (onWork)

Both functions are called with argument:
`js
const arg = {
isFullyOpened: true || false, // true only when Collapse reached final height
isFullyClosed: true || false, // true only when Collapse is fully closed and height is zero
isOpened: true || false, // true if Collapse has any non-zero height
containerHeight: 123, // current pixel height of Collapse container (changes until reaches contentHeight)
contentHeight: 123 // determined height of supplied Content
}
`

`js





`

Example example/App/Hooks.js

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`js
initialStyle: PropTypes.shape({
height: PropTypes.oneOfType([PropTypes.string, PropTypes.number]),
overflow: PropTypes.string
})
`

You may control initial element style, for example to force initial animation from 0 to height by using initialStyle={{height: '0px', overflow: 'hidden'}}

IMPORTANT Any updates to this prop will be ignored after first render.
Default value is determined based on initial isOpened value:
`js
initialStyle = props.isOpened
? {height: 'auto', overflow: 'initial'}
: {height: '0px', overflow: 'hidden'};
`

Example: example/App/ForceInitialAnimation.js

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Number in ms.

Collapse will check height after thins timeout to determine if animation is completed, the shorter the number - the faster onRest will be triggered and the quicker hight: auto will be applied. The downside - more calculations.
Default value is: 50.




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IMPORTANT Collapse does not support any pass-through props, so any non-supported props will be ignored

Because we need to have control over when Collapse component is updated and it is not possible or very hard to achieve when any random props can be passed to the component.




Behaviour notes

- initially opened Collapse elements will be statically rendered with no animation. You can override this behaviour by using initialStyle prop

- due to the complexity of margins and their potentially collapsible nature, ReactCollapse does not support (vertical) margins on their children. It might lead to the animation "jumping" to its correct height at the end of expanding. To avoid this, use padding instead of margin.
See #101 for more details




Migrating from v4 to v5

v5 was another complete rewrite that happened quite a while ago, it was published as @nkbt/react-collapse and tested in real projects for a long time and now fully ready to be used.

In the most common scenario upgrade is trivial (add CSS transition to collapse element), but if you were using a few deprecated props - there might be some extra work required.

Luckily almost every deprecated callback or prop has fully working analogue in v5. Unfortunately not all of them could maintain full backward compatibility, so please check this migration guide below.

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New Collapse does not implement animations anymore, it only determines Content height and updates Collapse wrapper height to match it.
Only after Collapse height reaches Content height (animation finished), Collapse's style is updated to have height: auto; overflow: initial.

The implications is that you will need to update your CSS with transition:
`css
.ReactCollapse--collapse {
transition: height 500ms;
}
`
IMPORTANT: without adding css transition there will be no animation and component will open/close instantly.

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- onRest/onWork callbacks (see above for full description). Though onRest did exist previously, now it is called with arguments containing few operational params and flags.

- initialStyle you may control initial element style, for example to force initial animation from 0 to height by using initialStyle={{height: '0px', overflow: 'hidden'}}
IMPORTANT Any updates to this prop will be ignored after first render.
Default value is:
`js
initialStyle = props.isOpened
? {height: 'auto', overflow: 'initial'}
: {height: '0px', overflow: 'hidden'};
`

- checkTimeout number in ms. Collapse will check height after thins timeout to determine if animation is completed, the shorter the number - the faster onRest will be triggered and the quicker hight: auto will be applied. The downside - more calculations.
Default value is: 50.

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- ~~Pass-through props~~ - any unknown props passed to Collapse component will be ignored

- ~~hasNestedCollapse~~ - no longer necessary, as v5 does not care if there are nested Collapse elements, see example/App/Nested.js

- ~~fixedHeight~~ - no longer necessary, just set whatever height you need for content element and Collapse will work as expected, see example/App/VariableHeight.js

- ~~springConfig~~ - as new Collapse relies on simple CSS transitions (or your own implementation of animation) and does not use react-collapse, springConfig is no longer necessary. You can control control animation with css like
`css
.ReactCollapse--collapse {
transition: height 500ms;
}
`

- ~~forceInitialAnimation~~ - you can use new prop initialStyle={{height: '0px', overflow: 'hidden'}} instead, so when new height will be set after component is rendered - it should naturally animate.

- ~~onMeasure~~ - please use onRest and onWork instead and pick contentHeight from argument
`js
onRest={({contentHeight}) => console.log(contentHeight)}
onWork={({contentHeight}) => console.log(contentHeight)}>




`
- ~~onRender~~ - since animations are fully controlled by external app (e.g. with CSS) we no draw each frame and do not actually re-render component anymore, so it is impossible to have onRender callback

Development and testing

Currently is being developed and tested with the latest stable Node on OSX.

To run example covering all ReactCollapse features, use yarn start, which will compile example/Example.js

`bash
git clone git@github.com:nkbt/react-collapse.git
cd react-collapse
yarn install
yarn start

then


open http://localhost:8080
`

Tests

`bash


to run ESLint check

yarn lint

to run tests

yarn test
``

License

MIT