declareEffect.ts

import { Store, ActionCreator } from '.'
import { identity } from './shared'

function declareEffect(cb) {}

type Step = {
  type: 'next' | 'catch' | string
  reducer: (promise: Promise<any>) => Promise<any>
}
class Flow {
  _steps: Step[]
  constructor(steps: Step[]) {
    this._steps = steps
  }

  next(onfulfilled: (...a: any) => any) {
    return new Flow(
      this._steps.concat({
        type: 'next',
        reducer: promise => promise.then(onfulfilled),
      }),
    )
  }

  catch(onrejected: (...a: any) => any) {
    return new Flow(
      this._steps.concat({
        type: 'catch',
        reducer: promise => promise.catch(onrejected),
      }),
    )
  }

  dispatch(actionCreator: ActionCreator, mapper = identity) {
    return new Flow(
      this._steps.concat({
        type: actionCreator.getType(),
        reducer: promise =>
          promise.next(function(payload) {
            this[STORE].dispatch(actionCreator(mapper(payload)))
            return payload
          }),
      }),
    )
  }

  run(store: Store, payload) {
    return this._steps.reduce(
      (acc, step) => step.reducer(acc),
      new Promise(r => r(payload)),
    )
  }
}