fix: tag search causing regex exception (#938)

app/assets/javascripts/utils/stringUtils.ts

@@ -0,0 +1,39 @@
+export const splitRangeWithinString = (
+  string: string,
+  start: number,
+  end: number
+) => {
+  const isStartOutOfBounds = start > string.length || start < 0;
+  const isEndOutOfBounds = end > string.length || end < 0;
+  const isInvalidRange = start > end;
+
+  if (isStartOutOfBounds || isEndOutOfBounds || isInvalidRange) {
+    return [string];
+  } else {
+    return [
+      string.slice(0, start),
+      string.slice(start, end),
+      string.slice(end),
+    ].filter((slice) => slice.length > 0);
+  }
+};
+
+export const getIndexOfQueryInString = (string: string, query: string) => {
+  const lowercasedTitle = string.toLowerCase();
+  const lowercasedQuery = query.toLowerCase();
+  return lowercasedTitle.indexOf(lowercasedQuery);
+};
+
+export const splitQueryInString = (string: string, query: string) => {
+  const indexOfQueryInTitle = getIndexOfQueryInString(string, query);
+
+  if (indexOfQueryInTitle < 0) {
+    return [string];
+  }
+
+  return splitRangeWithinString(
+    string,
+    indexOfQueryInTitle,
+    indexOfQueryInTitle + query.length
+  );
+};