Effector cheatsheet

effector.js

import {Stream, fromPromise} from 'most'
import {message, effect, Effect, Message} from 'effector'

type State = {
  currentUser: number,
}

/**
 * Plain async function
 */
async function fetchUserInfoCall(
  userId: number
): Promise<User> {
  return await invoke('UserInfo', { userId })
}


/** Incoming trigger */
const triggerUserInfo: Message<void>
  = message('need to request current user info')


/** Effect which represented our async call */
const requestUserInfo: Effect<number, User, UserNotFound>
  = effect('async api user info request')

/** Epic where we could get something from state and run effect */
triggerUserInfo.epic(
  (trigger$: Stream<void>, state$: Stream<State>) => state$
    .sampleWith(trigger$)
    .map(async ({ currentUser }) => {
      const error = await requestUserInfo(currentUser).fail()
      
      return warning({
        message: 'User not found!'
      })
    })
    .map(fromPromise)
    .join()
)

/** Subscription to messages about new requests */
requestUserInfo.epic( params$ => params$.tap(
  params => {
    console.log('Request started')
  }
))


requestUserInfo.done.epic( result$ => result$.tap(
  result => {
    console.log('Request done')
  }
))

requestUserInfo.fail.epic( error$ => error$.tap(
  error => {
    console.log('Request failed')
  }
))


/**
 * Now we need to provide implementation represented by requestUserInfo
 */
requestUserInfo.serve(fetchUserInfoCall)