web3.eth.getBlock("pending",(function(e,r){
           var b = r.transactions.length;
    console.log(b);
            console.log(web3.eth.mining);
           if (!e){
                if  (b > 0) {
            if (web3.eth.mining) return;
                console.log("== Pending transactions! Mining...");
                web3.miner.start(1);
            } else {
                web3.miner.stop(0);  // This param means nothing
                console.log("== No transactions! Mining stopped.");
        }

 }}))