Merge pull request #296 from glitch-soc/thread-mode

Threaded mode~

app/javascript/flavours/glitch/util/js_helpers.js

@@ -0,0 +1,5 @@
+//  This function returns the new value unless it is `null` or
+//  `undefined`, in which case it returns the old one.
+export function overwrite (oldVal, newVal) {
+  return newVal === null || typeof newVal === 'undefined' ? oldVal : newVal;
+}