message: null-guard defaultAvatarUrlForString
diff: @@ -82,6 +82,7 @@ function urlForColor(color) {
  const colorToDataURLCache = new Map();
  export function defaultAvatarUrlForString(s) {
  + if (!s) return "";
  const defaultColors = ['#0DBD8B', '#368bd6', '#ac3ba8'];
  let total = 0;
  for (let i = 0; i < s.length; ++i) {
  