How to get intermediate signals while calling 'snarkjs.groth16.fullProve()' in javascript ?

[VictorECDSA]

I am gonna write a circuit in circom, and call 'snarkjs.groth16.fullProve()' in javascript. I'd like to let javascript to get some intermediate signals of Circom, but I don't want those intermediate signals to be the output of Circom (so that reduce the size of the proof transaction when calling Solidity by reducing the public.json).

I've thought about adding some logs to circom, printing out the intermediate signal as log, and then javascript sends the last argument 'logger' when calling 'snarkjs.groth16.fullProve()', but I see that the 'logger' type is any, and I don't know how to construct this 'logger'. Is there a better way to implement my needs?

    function fullProve(
        _input: CircuitSignals,
        wasmFile: ZKArtifact,
        zkeyFileName: ZKArtifact,
        logger?: any,
    ): Promise<{
        proof: Groth16Proof;
        publicSignals: PublicSignals;
    }>;