interface Evaluation{
 compare(operator: string, lhs: unknown, rhs: unknown): boolean;
 realizeCondition(condition: string): Promise<ConditionResult>;
 factValue(factName: string, params?: Record<string, unknown>): Promise<unknown>;
 getValue(value: unknown): Promise<unknown>;
 emitEvent(event: Event): void;
}

async evaluate(evaluation: Evaluation): Promise<ConditionResult> {
 const [factResult, valueResult ] = await Promsei.all([
 evaluation.factValue(this.fact, this.params),
 evaluate.getValue(this.value)
 ]);
 const result = evaluation.compare(this.operator, factResult, valueResult);
 return {
 result,
 fact: this.fact,
 params: this.params,
 factResult,
 operation: this.operator,
 value: this.value,
 valueResult
 }
}

interface EvaluationTarget<TResult, TArgs extends any[]> {
 evaluate(evaluation: Evaluation, ...args: TArgs): TResult;
}
interface Evaluation {
 evaluate<TTarget extends EvaluationTarget<any, any[]>(
 target: TTarget,
 ...args: TTarget extends EvaluationTarget<any, infer TArgs> ? TArgs : never[]
 ): TTarget extends EvaluationTarget<infer TResult, any[]> ? TResult : never;
}

// Evaluation Targets act like plugins
import { factValue, getValue } from 'json-rules-engine/almanac';
import { comparison } from 'json-rules-engine/operator';
// Condition Class
async evaluate(evaluation: Evaluation): Promise<ConditionResult> {
 const [ factResult, valueResult ] = await Promise.all([
 evaluation.evaluate(factValue, this.fact, this.params),
 evaluation.evaluate(getValue, this.value)
 ]);
 const result = evaluation.evaluate(comparison, this.operator, factResult, valueResult);
 return {
 result,
 fact: this.fact,
 params: this.params,
 factResult,
 operation: this.operator,
 value: this.value,
 valueResult
 }
}