Fix stringification of AggregateErrors (#1651)

Author: isc-bsaviano

src/utils/index.ts

@@ -52,13 +52,13 @@ export const exportedUris: Set<string> = new Set();
 export const identifierRegex = /^(?:%|\p{L})[\p{L}\d]*$/u;
 
 /**
- * Return a string represenattion of `error`.
+ * Return a string representation of `error`.
  * If `error` is `undefined`, returns the empty string.
  */
 export function stringifyError(error): string {
  try {
- if (error instanceof AggregateError) {
- // Need to stringify the inner errors
+ if (Array.isArray(error?.errors)) {
+ // Need to stringify the inner errors of an AggregateError
  const errs = error.errors.map(stringifyError).filter((s) => s != "");
  return errs.length ? `AggregateError:\n- ${errs.join("\n- ")}` : "";
  }