70 lines
2.3 KiB
TypeScript
70 lines
2.3 KiB
TypeScript
// Copyright 2017-2019 @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 React, { useContext, useEffect, useState } from 'react';
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import { HeaderExtended } from '@polkadot/api-derive';
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import { ApiContext } from '@polkadot/react-api';
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import { formatNumber } from '@polkadot/util';
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interface Authors {
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byAuthor: Record<string, string>;
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lastBlockAuthor?: string;
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lastBlockNumber?: string;
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lastHeader?: HeaderExtended;
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lastHeaders: HeaderExtended[];
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}
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interface Props {
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children: React.ReactNode;
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}
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const MAX_HEADERS = 20;
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const byAuthor: Record<string, string> = {};
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const BlockAuthorsContext: React.Context<Authors> = React.createContext<Authors>({ byAuthor, lastHeaders: [] });
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function BlockAuthors ({ children }: Props): React.ReactElement<Props> {
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const { api } = useContext(ApiContext);
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const [state, setState] = useState<Authors>({ byAuthor, lastHeaders: [] });
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useEffect((): void => {
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// TODO We should really unsub - but since this should just be used once,
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// atm I'm rather typing this than doing it the way it is supposed to be
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api.isReady.then((): void => {
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let lastHeaders: HeaderExtended[] = [];
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api.derive.chain.subscribeNewHeads((lastHeader): void => {
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if (lastHeader && lastHeader.number) {
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const blockNumber = lastHeader.number.unwrap();
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const lastBlockAuthor = lastHeader.author ? lastHeader.author.toString() : undefined;
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const lastBlockNumber = formatNumber(blockNumber);
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if (lastBlockAuthor) {
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byAuthor[lastBlockAuthor] = lastBlockNumber;
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}
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lastHeaders = lastHeaders
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.filter((old, index): boolean => index < MAX_HEADERS && old.number.unwrap().lt(blockNumber))
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.reduce((next, header): HeaderExtended[] => {
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next.push(header);
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return next;
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}, [lastHeader])
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.sort((a, b): number => b.number.unwrap().cmp(a.number.unwrap()));
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setState({ byAuthor, lastBlockAuthor, lastBlockNumber, lastHeader, lastHeaders });
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}
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});
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});
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}, []);
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return (
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<BlockAuthorsContext.Provider value={state}>
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{children}
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</BlockAuthorsContext.Provider>
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);
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}
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export { BlockAuthorsContext, BlockAuthors };
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