PR Checklist

• The commit message follows our guidelines: https://github.com/nestjs/nest/blob/master/CONTRIBUTING.md
• Tests for the changes have been added (for bug fixes / features)
• Docs have been added / updated (for bug fixes / features)

PR Type

• Bugfix
• Feature

What is the current behavior?

Issue Number: #16095

setGlobalPrefix() only accepts a single string prefix. Users who need to expose the same API under multiple base paths (e.g., for different deployment environments) previously used regex-style prefixes like (prefixOne|prefixTwo), which are no longer supported by path-to-regexp v8 in NestJS v11.

What is the new behavior?

setGlobalPrefix() now accepts either a string or an array of strings:

// Single prefix (existing behavior)
app.setGlobalPrefix('api');

// Multiple prefixes (new)
app.setGlobalPrefix(['api', 'v1']);
// Routes will be registered under both /api/... and /v1/...

This provides a migration path for users who previously relied on regex-style prefixes.

Changes:

• Updated INestApplication.setGlobalPrefix() interface to accept string | string[]
• Added getGlobalPrefixes() method to ApplicationConfig to retrieve all prefixes
• Updated RoutePathFactory to generate paths for each prefix in the array
• Added unit tests for the new functionality

Does this PR introduce a breaking change?

• Yes
• No

The change is backward compatible - existing code using a single string prefix will continue to work.