Strategy.ts

interface WorkoutStrategy {
    fire(): void;
    stop?(): void;
  }
  
  class Running implements WorkoutStrategy {
    public fire(): void {
      console.log('Running')
    }
  }
  
  class Basketball implements WorkoutStrategy {
    public fire(): void {
      console.log('Basketball')
    }
  }
  
  class Swimming implements WorkoutStrategy {
    public fire(): void {
      console.log('Swimming')
    }
  }
  
  class Person {
    public strategy: WorkoutStrategy;
    public name: String;
    constructor(name: string, strategy: WorkoutStrategy) {
      this.name = name;
      this.strategy = strategy
    }
  
    workout(): void {
      console.log(`${ this.name } starts:`)
      this.strategy.fire();
    };
  }
  
// USAGE:
const amanda = new Person('Amanda', new Running());
amanda.workout();
// OUTPUT:
// "Amanda starts:"
// "Running"