@flaggr/evaluator

Standalone flag evaluation engine for Flaggr. Zero dependencies, pure TypeScript.

Use this package for local/edge evaluation when you want to evaluate feature flags without making API calls. The evaluation rules are cached locally and evaluated in-process for sub-millisecond latency.

Installation

npm install @flaggr/evaluator

Usage

import { evaluate } from '@flaggr/evaluator'

const result = evaluate({
  flag: {
    key: 'checkout-v2',
    type: 'boolean',
    enabled: true,
    defaultValue: false,
    targetingRules: [
      {
        conditions: [{ attribute: 'plan', operator: 'equals', value: 'enterprise' }],
        value: true,
      },
    ],
  },
  context: {
    targetingKey: 'user-123',
    plan: 'enterprise',
  },
})

console.log(result.value)  // true
console.log(result.reason) // "TARGETING_MATCH"

Features

• Zero dependencies
• Supports all 16 targeting operators
• Percentage rollouts with deterministic hashing
• Variant assignment for experiments
• Type-safe evaluation (boolean, string, number, object)

Documentation

• Advanced evaluation
• Targeting rules