checkmate is a Javascript tool that checks membership of events in blocks off-chain.

Inputs:

1. --abi - ABI for a smart contract
2. --event - Name of an event that can be fired by that smart contract
3. --params - Parameters for the event, in the correct order, provided as a space-separated list.

Output: The encoded event (as represented in Ethereum logs).

Inputs:

1. --blockhash - Hash of the block in which the transaction was mined.
2. --txhash - Hash of the transaction that fired the event.

Output: Merkle proof that the transaction was mined in the block.

Inputs:

1. --blockhash - Hash of the block in which the transaction was mined.
2. --txproof - Merkle proof that the transaction was mined in the block.
3. --logindex - Index of the log in the transaction.
4. --log - Encoded event (as represented in Ethereum logs).

Output: True if the event with the given log was fired in the transaction, false otherwise.