Dustin Boston

type Strategy<T> = {
  validate(value: T): boolean;
  algorithmInterface(): void;
};

// ConcreteStrategyA
export class EmailValidationStrategy implements Strategy<string> {
  validate(value: string): boolean {
    return /^[^\s@]+@[^\s@]+\.[^\s@]+$/.exec(value) !== null;
  }

  algorithmInterface(): void {
    console.log("ConcreteStrategyA");
  }
}

// ConcreteStrategyB
export class PhoneValidationStrategy implements Strategy<string> {
  validate(value: string): boolean {
    return /^(\+?\d{1,2}[-\s]?|)(?:\d{3}[-\s]?){2}\d{4}$/.exec(value) !== null;
  }

  algorithmInterface(): void {
    console.log("ConcreteStrategyB");
  }
}

// ConcreteStrategyC
export class MonthValidationStrategy implements Strategy<string> {
  validate(value: string): boolean {
    return (
      /^(Jan|Feb|March|Apr|May|Jun|Jul|Aug|Sep|Oct|Nov|Dec)$/.exec(value) !==
      null
    );
  }

  algorithmInterface(): void {
    console.log("ConcreteStrategyC");
  }
}

export class Context {
  constructor(private readonly strategy: Strategy<string>) {}

  // ContextInterface(): void {
  //   this.strategy.algorithmInterface();
  // }

  validate(value: string): boolean {
    return this.strategy.validate(value);
  }
}

import {describe, test, expect} from "bun:test";
import {
  Context,
  EmailValidationStrategy,
  MonthValidationStrategy,
  PhoneValidationStrategy,
} from "./code.ts";

describe("Strategy Pattern", () => {
  test("should validate email", () => {
    const context = new Context(new EmailValidationStrategy());
    const result = context.validate("no-reply@email.clutter");
    expect(result).toBe(true);
  });

  test("should validate phone", () => {
    const context = new Context(new PhoneValidationStrategy());
    const result = context.validate("123-456-7890");
    expect(result).toBe(true);
  });

  test("should validate month", () => {
    const context = new Context(new MonthValidationStrategy());
    const result = context.validate("Jan");
    expect(result).toBe(true);
  });
});