enbock / State-Value-Observer

export interface OnChangeCallback<Type> {

  (newValue: Type): void;

}

export interface ObserverAdapter<Type> {

  onChange: OnChangeCallback<Type>

}

export interface Observer<Type> {

  value: Type

}

export default class ValueObserver<Type> implements Observer<Type> {

  protected adapter: ObserverAdapter<Type>;

  protected current: Type;

  constructor(initialValue: Type, adapter: ObserverAdapter<Type>) {

    this.current = initialValue;

    this.adapter = adapter;

  }

  public get value(): Type {

    return this.current;

  }

  public set value(newValue: Type) {

    this.current = newValue;

    this.adapter.onChange(newValue);

  }

}