Binding Function interface idea

binding-function.ts

interface BindingFunction {
  /**
   * invoked by Aurelia when the binding is bound
   * updateView is a method that can be used to update the binding
   * parameters is an array of evaluated parameters passed to the binding at the time of binding
   */
  subscribe(updateView: (newValue) => void, parameters: Array<any>)

  /**
   * invoked by Aurelia when the binding or its parameters changes value
   * e.g. typing inside: <input value.bind="binding()">
   */
  onValue(value: any, parameters: Array<any>)

  /**
   * invoked by Aurelia when the binding invoked
   * e.g. clicking: <button click.trigger="binding()">
   */
  onInvocation(event: Event, parameters: Array<any>)

  /**
   * invoked by Aurelia when the binding is unbound
   * used for cleanup of things that were setup during subscribe
   */
  unsubscribe()
}