Migration of jsx files to tsx 2 (#850)

This is to continue the work of migrating all the jsx files into tsx
files.
The MO is basically described here: #848.

About 7 files to go...

src/components/Collapse.tsx

@@ -0,0 +1,34 @@
+import React from 'react'
+import { Collapse as ReactCollapse } from 'react-collapse'
+import {reducedMotionEnabled} from '../libs/accessibility'
+
+
+type CollapseProps = {
+  isActive: boolean
+  children: React.ReactElement
+};
+
+
+export default class Collapse extends React.Component<CollapseProps> {
+  static defaultProps = {
+    isActive: true
+  }
+
+  render() {
+    if (reducedMotionEnabled()) {
+      return (
+        <div style={{display: this.props.isActive ? "block" : "none"}}>
+          {this.props.children}
+        </div>
+      )
+    }
+    else {
+      return (
+        <ReactCollapse isOpened={this.props.isActive}>
+          {this.props.children}
+        </ReactCollapse>
+      )
+    }
+  }
+}
+