import { Patch } from '../diff'
import { Renderer } from './renderer'

export interface ReducerRenderer<Node> extends Renderer<Node> {
  reduceNode (node: Node, patch: Patch): Node
}

export const isReducer = <N>(renderer: Renderer<N>): renderer is ReducerRenderer<N> =>
  typeof renderer['reduceNode'] === 'function'

export interface BatchReducerRenderer<Node> extends ReducerRenderer<Node> {
  batchReduceNode (node: Node, patches: Patch[]): Node
}

export const isBatchReducer = <N>(reducer: ReducerRenderer<N>): reducer is BatchReducerRenderer<N> =>
  typeof reducer['batchReduceNode'] === 'function'