Introduce conversation details screen for New Groups

Co-authored-by: Chris Svenningsen <chris@carbonfive.com>
Co-authored-by: Sidney Keese <me@sidke.com>

ts/components/conversation/conversation-details/util.ts

@@ -0,0 +1,30 @@
+// Copyright 2020 Signal Messenger, LLC
+// SPDX-License-Identifier: AGPL-3.0-only
+
+import classNames from 'classnames';
+
+export const bemGenerator = (block: string) => (
+  element: string,
+  modifier?: string | Record<string, boolean>
+): string => {
+  const base = `${block}__${element}`;
+  const classes = [base];
+
+  let conditionals: Record<string, boolean> = {};
+
+  if (modifier) {
+    if (typeof modifier === 'string') {
+      classes.push(`${base}--${modifier}`);
+    } else {
+      conditionals = Object.keys(modifier).reduce(
+        (acc, key) => ({
+          ...acc,
+          [`${base}--${key}`]: modifier[key],
+        }),
+        {} as Record<string, boolean>
+      );
+    }
+  }
+
+  return classNames(classes, conditionals);
+};