blockscout/apps/block_scout_web/assets/js/pages/transactions.js

import $ from 'jquery'
import _ from 'lodash'
import URI from 'urijs'
import humps from 'humps'
import numeral from 'numeral'
import socket from '../socket'
import { createStore, connectElements, batchChannel, listMorph } from '../utils'

const BATCH_THRESHOLD = 10

export const initialState = {
  channelDisconnected: false,

  transactionCount: null,

  transactions: [],
  transactionsBatch: [],

  beyondPageOne: null
}

export function reducer (state = initialState, action) {
  switch (action.type) {
    case 'PAGE_LOAD':
    case 'ELEMENTS_LOAD': {
      return Object.assign({}, state, _.omit(action, 'type'))
    }
    case 'CHANNEL_DISCONNECTED': {
      return Object.assign({}, state, {
        channelDisconnected: true,
        transactionsBatch: []
      })
    }
    case 'RECEIVED_NEW_TRANSACTION_BATCH': {
      if (state.channelDisconnected) return state

      const transactionCount = state.transactionCount + action.msgs.length

      if (state.beyondPageOne) return Object.assign({}, state, { transactionCount })

      if (!state.transactionsBatch.length && action.msgs.length < BATCH_THRESHOLD) {
        return Object.assign({}, state, {
          transactions: [
            ...action.msgs.reverse(),
            ...state.transactions
          ],
          transactionCount
        })
      } else {
        return Object.assign({}, state, {
          transactionsBatch: [
            ...action.msgs.reverse(),
            ...state.transactionsBatch
          ],
          transactionCount
        })
      }
    }
    default:
      return state
  }
}

const elements = {
  '[data-selector="channel-disconnected-message"]': {
    render ($el, state) {
      if (state.channelDisconnected) $el.show()
    }
  },
  '[data-selector="channel-batching-count"]': {
    render ($el, state, oldState) {
      const $channelBatching = $('[data-selector="channel-batching-message"]')
      if (!state.transactionsBatch.length) return $channelBatching.hide()
      $channelBatching.show()
      $el[0].innerHTML = numeral(state.transactionsBatch.length).format()
    }
  },
  '[data-selector="transaction-count"]': {
    load ($el) {
      return { transactionCount: numeral($el.text()).value() }
    },
    render ($el, state, oldState) {
      if (oldState.transactionCount === state.transactionCount) return
      $el.empty().append(numeral(state.transactionCount).format())
    }
  },
  '[data-selector="transactions-list"]': {
    load ($el, store) {
      return {
        transactions: $el.children().map((index, el) => ({
          transactionHash: el.dataset.transactionHash,
          transactionHtml: el.outerHTML
        })).toArray()
      }
    },
    render ($el, state, oldState) {
      if (oldState.transactions === state.transactions) return
      const container = $el[0]
      const newElements = _.map(state.transactions, ({ transactionHtml }) => $(transactionHtml)[0])
      listMorph(container, newElements, { key: 'dataset.transactionHash' })
    }
  }
}

const $transactionListPage = $('[data-page="transaction-list"]')
if ($transactionListPage.length) {
  const store = createStore(reducer)
  store.dispatch({
    type: 'PAGE_LOAD',
    beyondPageOne: !!humps.camelizeKeys(URI(window.location).query(true)).index
  })
  connectElements({ store, elements })

  const transactionsChannel = socket.channel(`transactions:new_transaction`)
  transactionsChannel.join()
  transactionsChannel.onError(() => store.dispatch({
    type: 'CHANNEL_DISCONNECTED'
  }))
  transactionsChannel.on('transaction', batchChannel((msgs) => store.dispatch({
    type: 'RECEIVED_NEW_TRANSACTION_BATCH',
    msgs: humps.camelizeKeys(msgs)
  })))
}