Prototype Design Pattern — 3 Minute Series

Is creating a new instance too expensive? Try this!

Photo by Mark König on Unsplash

_00 / Concept

When you feel creating a new instance is expensive, then you can use Prototype Design Pattern to solve this problem. Remember, you need to know whether you are doing deep or shallow copy.

_01 / Key Roles

Clone method.

class Monster {
  ...states
  constructor() {
    this.init()
  }
  init() {
    ...super expensive process
  }
  clone() {    
    // shallow
    return Object.assign({}, this)
  }
}

_02 / Trade-offs

🟢 If the constructor process is too expensive, you might need it.
🟢 You can customize the cloning process if you need.
🟢 Alternative option for inheritance.
🔴 Shallow copy is always an issue, especially when your class depends on other objects.