[AI-FSSDK] [FSSDK-12369] Add local holdouts support with includedRules field

[Mat001]

Summary

This PR adds local holdouts support to the JavaScript SDK, allowing holdouts to target specific rules within a flag via an includedRules field.

Jira Ticket: FSSDK-12369

Changes

Type Definitions

• shared_types.ts: Added optional includedRules?: string[] | null to Holdout interface. Null/undefined = global holdout (applies to all rules); array = local holdout (targets specific rule IDs).

Configuration

• project_config/project_config.ts:
  • Added globalHoldouts: Holdout[] and ruleHoldoutsMap: { [ruleId: string]: Holdout[] } to ProjectConfig type
  • Updated parseHoldoutsConfig to classify holdouts as global or local based on includedRules
  • Added getHoldoutsForRule(projectConfig, ruleId) exported helper function

Decision Logic

• core/decision_service/index.ts:
  • Imported getHoldoutsForRule from project_config
  • Updated flag-level holdout check to use configObj.globalHoldouts instead of configObj.holdouts
  • Added local holdout check in getVariationFromExperimentRule (after forced decisions, before regular bucketing)
  • Added local holdout check in getVariationFromDeliveryRule (after forced decisions, before audience/bucketing)

Tests

• project_config/project_config.spec.ts: Added 6 new tests covering:
  • Global holdout classification (no includedRules)
  • Local holdout classification (with includedRules array)
  • Empty includedRules array = local, targets no rules
  • Multiple holdouts targeting same rule
  • getHoldoutsForRule helper function
  • Backward compatibility with old datafiles (no includedRules field)

Decision Flow

Flag evaluation
  └── Global holdouts (includedRules == null/undefined) → checked at flag level
        └── If not in global holdout:
              └── Forced decisions → checked per rule
                    └── Local holdouts (includedRules is array) → checked per rule
                          └── Regular bucketing / audience evaluation

Backward Compatibility

Old datafiles without includedRules have undefined for this field, which equals null in the == null check → treated as global holdout → behavior unchanged.

🤖 Generated with Claude Code

[coveralls]

coverage: 77.792% (-0.1%) from 77.906% — ai/mat001/FSSDK-12369-local-holdouts into master