fix: fix reduceMotion of svelte slide transition (#1237)

fixes #1236

src/routes/_components/compose/ComposeBox.html

@@ -98,7 +98,7 @@
   import { measureText } from '../../_utils/measureText'
   import { POST_PRIVACY_OPTIONS } from '../../_static/statuses'
   import { store } from '../../_store/store'
-  import { slide } from 'svelte-transitions'
+  import { slide } from '../../_transitions/slide'
   import { postStatus, insertHandleForReply, setReplySpoiler, setReplyVisibility } from '../../_actions/compose'
   import { classname } from '../../_utils/classname'
   import { POLL_EXPIRY_DEFAULT } from '../../_static/polls'

src/routes/_transitions/slide.js

@@ -0,0 +1,17 @@
+import { slide as svelteSlide } from 'svelte-transitions'
+import { store } from '../_store/store'
+import noop from 'lodash-es/noop'
+
+// same as svelte-transitions, but respecting reduceMotion
+export function slide (node, ref) {
+  let { reduceMotion } = store.get()
+  if (reduceMotion) {
+    return {
+      delay: 0,
+      duration: 1, // setting to 0 causes some kind of built-in duration
+      easing: _ => _,
+      css: noop
+    }
+  }
+  return svelteSlide(node, ref)
+}