@polkadot/react-query/Events.js

A collection of RxJs React components the Polkadot JS API

"use strict";

var _interopRequireWildcard = require("@babel/runtime/helpers/interopRequireWildcard");

Object.defineProperty(exports, "__esModule", {
  value: true
});
exports.Events = Events;
exports.EventsContext = void 0;

var _react = _interopRequireWildcard(require("react"));

var _reactHooks = require("@polkadot/react-hooks");

var _util = require("@polkadot/util");

var _utilCrypto = require("@polkadot/util-crypto");

// Copyright 2017-2020 @polkadot/react-query authors & contributors
// This software may be modified and distributed under the terms
// of the Apache-2.0 license. See the LICENSE file for details.
const MAX_EVENTS = 25;

const EventsContext = _react.default.createContext([]);

exports.EventsContext = EventsContext;

function Events({
  children
}) {
  const {
    api
  } = (0, _reactHooks.useApi)();
  const [state, setState] = (0, _react.useState)([]);
  (0, _react.useEffect)(() => {
    // TODO We should really unsub - but since this should just be used once,
    // atm I'm rather typing this than doing it the way it is supposed to be
    api.isReady.then(() => {
      const prevEventHash = '';
      let events = [];
      api.query.system.events(records => {
        const newEvents = records.filter(({
          event
        }) => event.section !== 'system').map((record, index) => ({
          key: "".concat(Date.now(), "-").concat(index),
          record
        }));
        const newEventHash = (0, _utilCrypto.xxhashAsHex)((0, _util.stringToU8a)(JSON.stringify(newEvents)));

        if (newEventHash !== prevEventHash) {
          events = [...newEvents, ...events].slice(0, MAX_EVENTS);
          setState(events);
        }
      });
    });
  }, []);
  return _react.default.createElement(EventsContext.Provider, {
    value: state
  }, children);
}