Support for EIP 1898

[mshakeg]

Describe the Feature

Most json rpc relays such as Infura and Alchemy support EIP-1898, however as far as I can tell there's no way in ethers to use the blockHash on the supported methods as only blockTag(i.e. block number) is supported.

Add support all methods that EIP-1898 affects:

• eth_getBalance
• eth_getStorageAt
• eth_getTransactionCount
• eth_getCode
• eth_call
• eth_getProof

Code Example

For example say a dev wants to query contract state at a specific blockNumber, they can do so with the current blockTag implementation as follows:

const result = await someContract.someFunction({
  blockTag: someBlockNumber
});

Similarly they may want to query by blockHash and they should be able to do so as follows:

const result = await someContract.someFunction({
  blockHash: someBlockHash
});

[ricmoo]

You should be able to pass a blockHash in as a blockTag. Keep in mind that if a backend does not support it, it is (unfortunately) silently ignored and "latest" is used with no way to detect it was ignored.