Q:

how to memoize a TypeScript getter

I am using the following approach to memoize a TypeScript getter using a decorator but wanted to know if there is a better way. I am using the popular memoizee package from npm as follows:
import { memoize } from '@app/decorators/memoize'

export class MyComponent {

  @memoize()
  private static memoizeEyeSrc(clickCount, maxEyeClickCount, botEyesDir) {
    return clickCount < maxEyeClickCount ? botEyesDir + '/bot-eye-tiny.png' : botEyesDir + '/bot-eye-black-tiny.png'
  }

  get leftEyeSrc() {
    return MyComponent.memoizeEyeSrc(this.eyes.left.clickCount, this.maxEyeClickCount, this.botEyesDir)
  }
}

AND the memoize decorator is:
// decorated method must be pure
import * as memoizee from 'memoizee'

export const memoize = (): MethodDecorator => {
  return (target: any, propertyKey: string, descriptor: PropertyDescriptor) => {
    const func = descriptor.value
    descriptor.value = memoizee(func)
    return descriptor
  }
}

Is there a way to do this without using two separate functions in MyComponent and to add the decorator directly to the TypeScript getter instead?
One consideration here is that the decorated function must be pure (in this scenario) but feel free to ignore that if you have an answer that doesn't satisfy this as I have a general interest in how to approach this problem.

A:

The decorator can be extended to support both prototype methods and getters:
export const memoize = (): MethodDecorator => {
  return (target: any, propertyKey: string, descriptor: PropertyDescriptor) => {
    if ('value' in descriptor) {
      const func = descriptor.value;
      descriptor.value = memoizee(func);
    } else if ('get' in descriptor) {
      const func = descriptor.get;
      descriptor.get = memoizee(func);
    }
    return descriptor;
  }
}

And be used directly on a getter:
  @memoize()
  get leftEyeSrc() {
    ...
  }

