@vechain/sdk-network/src/provider/utils/rpc-mapper/methods/eth_syncing/eth_syncing.ts

This module serves as the standard interface connecting decentralized applications (dApps) and users to the VeChainThor blockchain

import { HexInt } from '@vechain/sdk-core';
import { JSONRPCInternalError, stringifyData } from '@vechain/sdk-errors';
import {
    type CompressedBlockDetail,
    type ThorClient
} from '../../../../../thor-client';
import { blocksFormatter, type SyncBlockRPC } from '../../../formatter';
import { ethChainId } from '../eth_chainId';

/**
 * Check if the block is out of sync in time.
 * A block is considered out of sync if the difference between the current time and the block timestamp is GREATER than 11 seconds.
 *
 * @param block - Block to check
 */
const _isBlockNotOutOfSyncInTime = (block: CompressedBlockDetail): boolean => {
    return Math.floor(Date.now() / 1000) - block.timestamp < 11000;
};

/**
 * RPC Method eth_syncing implementation
 *
 * @link [eth_syncing](https://ethereum.github.io/execution-apis/api-documentation/)
 *
 * @param thorClient - The thor client instance to use.
 *
 * @note The startingBlock parameter is not supported.
 *
 * @returns Returns an object with the sync status of the node if the node is out-of-sync and is syncing. Returns false when the node is already in sync.
 */
const ethSyncing = async (
    thorClient: ThorClient
): Promise<boolean | SyncBlockRPC> => {
    try {
        // Get the best block and the genesis block
        const bestBlock = await thorClient.blocks.getBestBlockCompressed();
        const genesisBlock = await thorClient.blocks.getGenesisBlock();

        // Get the highest block number
        const highestBlockNumber: string | null =
            genesisBlock !== null
                ? HexInt.of(
                      Math.floor((Date.now() - genesisBlock.timestamp) / 10000)
                  ).toString()
                : null;

        // Check the latest block
        if (bestBlock !== null) {
            // Check if the node is out of sync
            if (_isBlockNotOutOfSyncInTime(bestBlock)) return false;

            // Calculate the chainId
            const chainId = await ethChainId(thorClient);

            return {
                currentBlock: blocksFormatter.formatToRPCStandard(
                    bestBlock,
                    chainId
                ),
                highestBlock: highestBlockNumber,

                // Not supported field
                startingBlock: null
            };
        }

        // Strange cases when the fetched best block is null
        return {
            currentBlock: null,
            highestBlock: highestBlockNumber,

            // Not supported field
            startingBlock: null
        };
    } catch (e) {
        throw new JSONRPCInternalError(
            'eth_syncing()',
            'Method "eth_syncing" failed.',
            {
                url: thorClient.httpClient.baseURL,
                innerError: stringifyData(e)
            }
        );
    }
};

export { ethSyncing };