solidity:通过js设置监听事件

参考文章

1、合约代码

pragma solidity ^0.4.21;
 
contract Coin{
    address public minter;
    mapping (address=> uint) public balances;
 
    event LogSend(address from, address to, uint amount);
 
    constructor () public {
        minter = msg.sender;
    }
 
    function min(address receiver, uint amount) public {
        if (msg.sender != minter) return ;
        balances[receiver] += amount;
    }
 
    function send(address receiver, uint amount) public {
        if (balances[msg.sender] < amount) return;
        balances[msg.sender] -= amount;
        balances[receiver] += amount;
        emit LogSend(msg.sender, receiver, amount);
    }
 
}

2、设置事件

var myEvent = counter.LogSend();
myEvent.watch(function(err, result){
    if (!err){
        console.log(result)
    } else {
        console.log(err);
    }
    myEvent.stopWatching();
});
 
转账：
> personal.unlockAccount(eth.accounts[0], "lyh001", 300)
> counter.send(eth.accounts[1], 1)
> miner.start(1); admin.sleepBlocks(1); miner.stop();
此时，可以看到有相关的交易事件输出
> counter.balances(eth.accounts[0])