Get rid of Collapsable, use CSS instead

Change inspired by a6ddd1aba2

app/javascript/flavours/glitch/components/collapsable.js

@@ -1,22 +0,0 @@
-import React from 'react';
-import Motion from 'flavours/glitch/util/optional_motion';
-import spring from 'react-motion/lib/spring';
-import PropTypes from 'prop-types';
-
-const Collapsable = ({ fullHeight, isVisible, children }) => (
-  <Motion defaultStyle={{ opacity: !isVisible ? 0 : 100, height: isVisible ? fullHeight : 0 }} style={{ opacity: spring(!isVisible ? 0 : 100), height: spring(!isVisible ? 0 : fullHeight) }}>
-    {({ opacity, height }) =>
-      (<div style={{ height: `${height}px`, overflow: 'hidden', opacity: opacity / 100, display: Math.floor(opacity) === 0 ? 'none' : 'block' }}>
-        {children}
-      </div>)
-    }
-  </Motion>
-);
-
-Collapsable.propTypes = {
-  fullHeight: PropTypes.number.isRequired,
-  isVisible: PropTypes.bool.isRequired,
-  children: PropTypes.node.isRequired,
-};
-
-export default Collapsable;

app/javascript/flavours/glitch/features/composer/spoiler/index.js

@@ -3,9 +3,6 @@ import React from 'react';
 import PropTypes from 'prop-types';
 import { defineMessages, FormattedMessage } from 'react-intl';
 
-//  Components.
-import Collapsable from 'flavours/glitch/components/collapsable';
-
 //  Utils.
 import {
   assignHandlers,
@@ -59,11 +56,8 @@ export default class ComposerSpoiler extends React.PureComponent {
 
     //  The result.
     return (
-      <Collapsable
-        isVisible={!hidden}
-        fullHeight={50}
-      >
-        <label className='composer--spoiler'>
+      <div className={`composer--spoiler ${hidden ? '' : 'composer--spoiler--visible'}`}>
+        <label>
           <span {...hiddenComponent}>
             <FormattedMessage {...messages.placeholder} />
           </span>
@@ -76,7 +70,7 @@ export default class ComposerSpoiler extends React.PureComponent {
             value={text}
           />
         </label>
-      </Collapsable>
+      </div>
     );
   }
 

app/javascript/flavours/glitch/styles/components/composer.scss

@@ -2,7 +2,20 @@
   padding: 10px;
 }
 
+.no-reduce-motion .composer--spoiler {
+  transition: height 0.4s ease, opacity 0.4s ease;
+}
+
 .composer--spoiler {
+  height: 0;
+  transform-origin: bottom;
+  opacity: 0.0;
+
+  &.composer--spoiler--visible {
+    height: 47px;
+    opacity: 1.0;
+  }
+
   input {
     display: block;
     box-sizing: border-box;