Adapters

Each adapter wraps a client/provider you've already constructed — neither one ever creates its own, so you stay in full control of chain/transport configuration (RPC URL, chain ID, retries, …).

createViemAdapter

import {createViemAdapter} from '@ethereum-radio/indexer/adapters/viem';

function createViemAdapter(client: PublicClient): LogsProvider;

Requires viem (optional peer dependency — see Installation).

viem's typed getLogs action only supports ABI event-based filtering (event/events/args), not arbitrary raw topics — since this package deliberately stays ABI-decoding-agnostic (see Core), the adapter instead calls the raw eth_getLogs JSON-RPC method directly (client.request({method: 'eth_getLogs', ...})) and formats each result with viem's own formatLog, mirroring what viem's getLogs does internally before it hands off to ABI decoding.

Gotcha: without an explicit chain config, viem's getBlockNumber() defaults to a 4-second cacheTime — fine for typical polling, but if you're driving createRadio/radio() with a short pollIntervalMs, the client can keep returning a stale cached tip for up to 4 real seconds after a new block lands. Pass cacheTime: 0 (or a chain config with an accurate block time) to createPublicClient if you want fast polling to actually see new blocks promptly.

Also implements getBlockHash (via client.getBlock({blockNumber})), needed for Cursor.checkForReorg.

createEthersAdapter

import {createEthersAdapter} from '@ethereum-radio/indexer/adapters/ethers';

function createEthersAdapter(provider: Provider): LogsProvider;

Requires ethers (optional peer dependency — see Installation).

Normalizes the two places ethers v6's shape differs from viem's: provider.getBlockNumber() returns a plain number (wrapped in BigInt(...) here), and a log's index field is named index rather than logIndex.

Also implements getBlockHash (via provider.getBlock(blockNumber)), needed for Cursor.checkForReorg.

Why an adapter at all?

Both libraries expose a native, stateless getLogs(filter) and getBlockNumber() — normalizing them to one shared LogsProvider interface is what lets Cursor/createRadio/chunkedFetchLogs work identically regardless of which client library you use. It also sidesteps a subtler issue: a naive chunked fetcher built on createContractEventFilter + getFilterLogs (a server-side filter handle) can silently misbehave against a round-robin/load-balanced RPC backend, since the filter's state may not exist on whichever backend node answers the next call. Both adapters here call the stateless getLogs once per window instead, which has no such failure mode.