index.js

/*
 * To tie everything together, we must instantiate our Action Handler and Action Reader, and instantiate an Action
 * Watcher with both of those.
 */

const { BaseActionWatcher } = require("demux")
const { NodeosActionReader } = require("demux-eos") // eslint-disable-line
const ObjectActionHandler = require("./ObjectActionHandler")
const handlerVersion = require("./handlerVersions/v1")

/*
 * This ObjectActionHandler, which does not change the signature from its parent AbstractActionHandler, takes an array
 * of `HandlerVersion` objects
 */
const actionHandler = new ObjectActionHandler([handlerVersion])

/*
 * Since we're reading from the EOS main net, we can use the NodeosActionReader supplied by the demux-eos package. This
 * utilizes any public Nodeos endpoint as a source of block data.
 *
 * The second argument defines at what block this should start at. For values less than 1, this switches to a "tail"
 * mode, where we start at an offset of the most recent blocks.
 *
 * More information can be found on the main demux-eos repository:
 * https://github.com/EOSIO/demux-js-eos
 */
const actionReader = new NodeosActionReader({
  startAtBlock: 50000000,
  onlyIrreversible: false,
  nodeosEndpoint: "https://api.eosnewyork.io"
})

/* BaseActionWatcher
 * This ready-to-use base class helps coordinate the Action Reader and Action Handler, passing through block information
 * from the Reader to the Handler. The third argument is the polling loop interval in milliseconds. Since EOS has 0.5s
 * block times, we set this to half that for an average of 125ms latency.
 *
 * All that is left to run everything is to call `watch()`.
 */
const actionWatcher = new BaseActionWatcher(
  actionReader,
  actionHandler,
  250,
)

actionWatcher.watch()