Lazy.ts

export type Lazy<T, TArgs = void> = {
  isInitialized(): boolean
  get(args: TArgs): T
  update(data: T)
  clear(): Lazy<T>
}

export const lazy = <T, TArgs = void>(loader: (args: TArgs) => T) => {
  let initialized = false
  let lazy: T | undefined
  return {
    isInitialized: () => initialized,
    get: (args: TArgs) => {
      if (lazy) return lazy
      initialized = true
      lazy = loader(args)
      return lazy
    },
    clear: () => {
      lazy = undefined
      initialized = false
    },
    update: (data: T) => {
      lazy = data
      initialized = true
    }
  } as Lazy<T, TArgs>
}