Flyweight.ts

interface Action {
    move(location: [number, number]): void;
    shoot?(target: string, location: [number, number]): void;
    cure?(mate: string, location: [number, number]): void;
  }
  
  class Soldier implements Action {
  
    private equipmentSet: string;
    number: number;
  
    constructor(set: string, number: number) {
      // initialization consumes time
      this.equipmentSet = set;
      this.number = number;
      console.log(`new soldier ${number}`);
    }
  
    move(location: [number, number]): void {
      console.log(`move to ${location}`)
    }
  
    shoot?(target: string, location: [number, number]): void {
      console.log(`damage ${target} at ${location}`);
    }
  
    cure?(mate: string, location: [number, number]): void {
      console.log(`cure ${mate} at ${location}`);
    }
  }
  
  class SoldierAcademy {
    private static groups: { [set: string]: Soldier } = {}
  
    public static getSoldier(set: string, num: number) {
      let soldier = SoldierAcademy.groups[set];
  
      if (!soldier) {
        soldier = new Soldier(set, num);
        SoldierAcademy.groups[set] = soldier;
      } else {
        soldier.number = num;
        console.log(`shared soldier ${soldier.number}`);
      }
  
      return soldier;
    }
  }
  
// USAGE:
const start = Math.floor(Date.now());
for (let i = 0; i < 1000; i++) {
  // new Soldier('normal-set', i); // create 1m real soldiers
  SoldierAcademy.getSoldier('normal-set', i); // create 1 soldier
}
const end = Math.floor(Date.now());
console.log(end - start);
// OUTPUT:
// "new soldier 0" 
// "shared soldier 1" 
// "shared soldier 2" 
// ...
// "shared soldier 999" 
// 5409