Add items to a list

Index.hs

{-# LANGUAGE OverloadedStrings #-}
{-# LANGUAGE RecursiveDo #-}

import Control.Lens

import Data.Text (Text)
import qualified Data.Text as Text

import Data.Map (Map)
import qualified Data.Map as Map

import Data.Set (Set)
import qualified Data.Set as Set

import Reflex.Collection
import Reflex.Time

import Reflex.Dom

main :: IO ()
main = mdo
  mainWidget $ do
  el "h1" $ text "Reflex FRP Autocomplete Example - Canva Frontend Meetup"
  el "h2" $ text "Part 3 - Adding items to a list"
  el "section" $ do
    eAdd <- addItem
    dMap <- itemsMap eAdd
    pure ()

addItem :: MonadWidget t m => m (Event t Text)
addItem = mdo
  addItemText <- textInput $ def
    & setValue .~ ("" <$ eAddItemClick)
  eAddItemClick <- button "Add"
  let eAtClick = Text.strip <$> current (value addItemText) <@ eAddItemClick

  pure eAtClick

itemsMap :: MonadWidget t m => Event t Text -> m (Dynamic t (Map Int Text))
itemsMap eAdd = do
  dCount <- count eAdd
  dMap <- foldDyn ($) Map.empty $
    Map.insert <$> current dCount <@> eAdd

  _ <- el "ul" . list dMap $
         el "li" . dynText

  pure dMap