c60ba8708a
* Bumps w/ eslint * Additional * Additional * Additional * Additional * Remove style props * Additional * Additional * Additional * Additional (< 100) * eslint passes, tsc next * tsc fixes * Update deps * Update i18n
88 lines
2.6 KiB
TypeScript
88 lines
2.6 KiB
TypeScript
// Copyright 2017-2020 @polkadot/react-query authors & contributors
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// This software may be modified and distributed under the terms
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// of the Apache-2.0 license. See the LICENSE file for details.
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import { BlockNumber, EventRecord } from '@polkadot/types/interfaces';
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import React, { useEffect, useState } from 'react';
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import { useApi } from '@polkadot/react-hooks';
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import { stringToU8a } from '@polkadot/util';
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import { xxhashAsHex } from '@polkadot/util-crypto';
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interface IndexedEvent {
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index: number;
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record: EventRecord;
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}
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interface KeyedEvent extends IndexedEvent {
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blockHash: string;
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blockNumber: BlockNumber;
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key: string;
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}
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type Events = KeyedEvent[];
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interface Props {
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children: React.ReactNode;
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}
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const MAX_EVENTS = 50;
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const EventsContext: React.Context<Events> = React.createContext<Events>([]);
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function EventsBase ({ children }: Props): React.ReactElement<Props> {
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const { api } = useApi();
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const [state, setState] = useState<Events>([]);
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useEffect((): void => {
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// No unsub, global context - destroyed on app close
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api.isReady.then((): void => {
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let prevBlockHash: string | null = null;
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let prevEventHash: string | null = null;
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api.query.system.events((records): void => {
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const newEvents: IndexedEvent[] = records
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.map((record, index) => ({ index, record }))
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.filter(({ record: { event: { section } } }) => section !== 'system');
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const newEventHash = xxhashAsHex(stringToU8a(JSON.stringify(newEvents)));
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if (newEventHash !== prevEventHash && newEvents.length) {
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prevEventHash = newEventHash;
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// retrieve the last header, this will map to the current state
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api.rpc.chain.getHeader().then((header): void => {
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const blockNumber = header.number.unwrap();
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const blockHash = header.hash.toHex();
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if (blockHash !== prevBlockHash) {
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prevBlockHash = blockHash;
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setState((events) => [
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...newEvents.map(({ index, record }): KeyedEvent => ({
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blockHash,
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blockNumber,
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index,
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key: `${blockNumber.toNumber()}-${blockHash}-${index}`,
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record
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})),
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...events
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].slice(0, MAX_EVENTS));
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}
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}).catch(console.error);
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}
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}).catch(console.error);
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}).catch(console.error);
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// eslint-disable-next-line react-hooks/exhaustive-deps
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}, []);
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return (
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<EventsContext.Provider value={state}>
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{children}
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</EventsContext.Provider>
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);
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}
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const Events = React.memo(EventsBase);
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export { EventsContext, Events };
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