test: harden onboarding route coverage

ui/src/lib/onboarding-route.ts

@@ -0,0 +1,51 @@
+type OnboardingRouteCompany = {
+  id: string;
+  issuePrefix: string;
+};
+
+export function isOnboardingPath(pathname: string): boolean {
+  const segments = pathname.split("/").filter(Boolean);
+
+  if (segments.length === 1) {
+    return segments[0]?.toLowerCase() === "onboarding";
+  }
+
+  if (segments.length === 2) {
+    return segments[1]?.toLowerCase() === "onboarding";
+  }
+
+  return false;
+}
+
+export function resolveRouteOnboardingOptions(params: {
+  pathname: string;
+  companyPrefix?: string;
+  companies: OnboardingRouteCompany[];
+}): { initialStep: 1 | 2; companyId?: string } | null {
+  const { pathname, companyPrefix, companies } = params;
+
+  if (!isOnboardingPath(pathname)) return null;
+
+  if (!companyPrefix) {
+    return { initialStep: 1 };
+  }
+
+  const matchedCompany =
+    companies.find(
+      (company) =>
+        company.issuePrefix.toUpperCase() === companyPrefix.toUpperCase(),
+    ) ?? null;
+
+  if (!matchedCompany) {
+    return { initialStep: 1 };
+  }
+
+  return { initialStep: 2, companyId: matchedCompany.id };
+}
+
+export function shouldRedirectCompanylessRouteToOnboarding(params: {
+  pathname: string;
+  hasCompanies: boolean;
+}): boolean {
+  return !params.hasCompanies && !isOnboardingPath(params.pathname);
+}