Examples for Rapt Medium story

rapt-example-1.js

import {Map} from 'immutable'

// without Rapt
const processUser = user => {
  log(user)
  let userMap = Map(user)
  if (emailHasBeenVerified) {
    userMap = userMap.set('verified', true)
  }
  syncWithServer(userMap)
  return userMap
}

// with Rapt
const processUser = user =>
  rapt(user)
    .tap(log)
    .map(Map)
    .mapIf(emailHasBeenVerified, u => u.set('verified', true))
    .tap(syncWithServer)
    .val()

rapt-example-2.js

import _ from 'lodash'

// without Rapt
const countItems = (shouldFilter, hugeArrayOfItems) => {
  let arr = _.compact(hugeArrayOfItems)
  if (shouldFilter) {
    arr = arr.filter(expensiveFilterFunction)
  }
  const count = arr.length
  console.log(`We have ${count} items`)
  return count
}

// with Rapt
const countItems = (shouldFilter, hugeArrayOfItems) =>
  rapt(hugeArrayOfItems)
    .map(compact)
    .mapIf(shouldFilter, arr => arr.filter(expensiveFilterFunction))
    .map(items => items.length)
    .tap(count => console.log(`We have ${count} items`))
    .val()