ghost-portal/packages/react-query/src/BlockAuthors.tsx
2019-11-16 20:21:46 +01:00

79 lines
2.6 KiB
TypeScript

// Copyright 2017-2019 @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.
import React, { useEffect, useState } from 'react';
import { HeaderExtended } from '@polkadot/api-derive';
import { useApi } from '@polkadot/react-hooks';
import { formatNumber } from '@polkadot/util';
interface Authors {
byAuthor: Record<string, string>;
lastBlockAuthors?: string[];
lastBlockNumber?: string;
lastHeader?: HeaderExtended;
lastHeaders: HeaderExtended[];
}
interface Props {
children: React.ReactNode;
}
const MAX_HEADERS = 25;
const byAuthor: Record<string, string> = {};
const BlockAuthorsContext: React.Context<Authors> = React.createContext<Authors>({ byAuthor, lastHeaders: [] });
function BlockAuthors ({ children }: Props): React.ReactElement<Props> {
const { api } = useApi();
const [state, setState] = useState<Authors>({ byAuthor, lastHeaders: [] });
useEffect((): void => {
// 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((): void => {
let lastHeaders: HeaderExtended[] = [];
let lastBlockAuthors: string[] = [];
let lastBlockNumber = '';
api.derive.chain.subscribeNewHeads((lastHeader): void => {
if (lastHeader?.number) {
const blockNumber = lastHeader.number.unwrap();
const thisBlockAuthor = lastHeader.author?.toString();
const thisBlockNumber = formatNumber(blockNumber);
if (thisBlockAuthor) {
byAuthor[thisBlockAuthor] = thisBlockNumber;
if (thisBlockNumber !== lastBlockNumber) {
lastBlockNumber = thisBlockNumber;
lastBlockAuthors = [thisBlockAuthor];
} else {
lastBlockAuthors.push(thisBlockAuthor);
}
}
lastHeaders = lastHeaders
.filter((old, index): boolean => index < MAX_HEADERS && old.number.unwrap().lt(blockNumber))
.reduce((next, header): HeaderExtended[] => {
next.push(header);
return next;
}, [lastHeader])
.sort((a, b): number => b.number.unwrap().cmp(a.number.unwrap()));
setState({ byAuthor, lastBlockAuthors: lastBlockAuthors.slice(), lastBlockNumber, lastHeader, lastHeaders });
}
});
});
}, []);
return (
<BlockAuthorsContext.Provider value={state}>
{children}
</BlockAuthorsContext.Provider>
);
}
export { BlockAuthorsContext, BlockAuthors };