feat: add methods to retrieve domains for users and roles

[Copilot]

Users need to retrieve all domains associated with a user or role without manually iterating through policies. The Go Casbin library has getDomain functionality, but node-casbin lacked equivalent methods.

This implementation follows the exact Go Casbin pattern, architecture, and test cases to ensure compatibility.

Changes

RoleManager Interface - Added methods matching Go Casbin:

• getDomains(name: string): Gets domains that a user has
• getAllDomains(): Gets all domains

DefaultRoleManager - Implemented RoleManager methods:

• Checks if a role has roles (inherits from) OR users (inherited by)
• Filters out default domain when other domains exist (matching Go behavior)
• Follows Go DomainManager implementation pattern

Enforcer - Added user-facing RBAC methods:

• getDomainsForUser(user): Returns all domains for a user by calling RoleManager
• getAllDomains(): Returns all domains by calling RoleManager
• Methods are in Enforcer class (not ManagementEnforcer), matching Go Casbin's rbac_api.go

Test Coverage

• Added rbac_with_domains_policy2.csv matching Go Casbin test data
• Test cases match Go Casbin's test patterns and naming exactly
• All 186 tests pass

Usage

const e = await newEnforcer('rbac_with_domains_model.conf', 'rbac_with_domains_policy2.csv');

// Get all domains in the system
const domains = await e.getAllDomains();  // ['domain1', 'domain2']

// Get domains for specific user
const userDomains = await e.getDomainsForUser('alice');  // ['domain1', 'domain2']

// Check domain access
if (userDomains.includes('domain1')) {
  // grant access
}

Policy example:

g, alice, admin, domain1
g, alice, admin, domain2
g, bob, admin, domain2
g, bob, user, domain3

Original prompt

---

This section details on the original issue you should resolve

<issue_title>Feature Request: Method to Retrieve All Domains for a User or a role</issue_title>
<issue_description>I noticed that the Casbin Go library includes a function getDomain. However, I'm looking for a method to retrieve all domains for a user without having to manually iterate over all policies.

Is there an existing method to get all domains for a user more efficiently, or is there a recommended approach to achieve this?

Thank you!</issue_description>

Comments on the Issue (you are @copilot in this section)

• Fixes Feature Request: Method to Retrieve All Domains for a User or a role #479

---

✨ Let Copilot coding agent set things up for you — coding agent works faster and does higher quality work when set up for your repo.

[CLAassistant]

Thank you for your submission! We really appreciate it. Like many open source projects, we ask that you sign our Contributor License Agreement before we can accept your contribution.
_{You have signed the CLA already but the status is still pending? Let us recheck it.}

[coveralls]

Pull Request Test Coverage Report for Build 20033979759

Details

• 28 of 29 (96.55%) changed or added relevant lines in 2 files are covered.
• No unchanged relevant lines lost coverage.
• Overall coverage increased (+0.2%) to 78.299%

---

Changes Missing Coverage	Covered Lines	Changed/Added Lines	%
src/rbac/defaultRoleManager.ts	18	19	94.74%

Totals
Change from base Build 20034893874:	0.2%
Covered Lines:	1625
Relevant Lines:	1977

---

💛 - Coveralls

[mserico]

@copilot should exactly use the same behavior as Go Casbin, including code and test cases and naming patterns

[Copilot]

@copilot should exactly use the same behavior as Go Casbin, including code and test cases and naming patterns

Updated to match Go Casbin exactly:

✅ Added getDomains() and getAllDomains() to RoleManager interface
✅ Implemented in DefaultRoleManager following Go pattern
✅ Methods are in Enforcer (rbac_api), not ManagementEnforcer
✅ Created rbac_with_domains_policy2.csv matching Go test data
✅ Test cases match Go Casbin test patterns and naming
✅ Filters default domain when other domains exist (Go behavior)

All 186 tests pass. See commit 2ba42d1 for the final implementation.