console에서 web3 transaction 실행

REF

브라우저의 console에서도 web3로 contract를 실행할 수 있다.  

작년에 작성된 것이긴 하지만, ERC20 token을 전송하는 transfer를 아래와 같이 console로 수행가능하다.

 ==> 이를 응용하면 개발중인 화면에서, 유사방식으로 실행하면서 debugging이 가능하다. 

> const Web3 = require('web3');
undefined
> const web3 = new Web3('http://localhost:8545');
undefined
> web3.version
'1.0.0-beta.11'
> fs = require('fs');
<blah>
> const abi = fs.readFileSync('erc20_abi.json', 'utf-8');
undefined
> const contract = new web3.eth.Contract(JSON.parse(abi), '0xafb7b8a4d90c2df4ce640338029d54a55bedcfc4', { from: '0x90f8bf6a479f320ead074411a4b0e7944ea8c9c1', gas: 100000});
undefined
> contract.methods.balanceOf('0x90f8bf6a479f320ead074411a4b0e7944ea8c9c1').call().then(console.log).catch(console.error);
Promise {...}
> 99997
> contract.methods.transfer('0xffcf8fdee72ac11b5c542428b35eef5769c409f0', 1).send().then(console.log).catch(console.error);
Promise {...}
> { transactionHash: '0xf2d621ba5029a086e212d87fab83be31c3fa41fe47198c378f55c252e5b25d5b',
  transactionIndex: 0,
  blockHash: '0x0e806bf3e88f9335ee9be903303a2393c940ab22f4a73c7e28ca8d9a212ffa4e',
  blockNumber: 429,
  gasUsed: 35206,
  cumulativeGasUsed: 35206,
  contractAddress: null,
  events: 
   { Transfer: 
      { logIndex: 0,
        transactionIndex: 0,
        transactionHash: '0xf2d621ba5029a086e212d87fab83be31c3fa41fe47198c378f55c252e5b25d5b',
        blockHash: '0x0e806bf3e88f9335ee9be903303a2393c940ab22f4a73c7e28ca8d9a212ffa4e',
        blockNumber: 429,
        address: '0xAFB7b8A4d90C2Df4ce640338029d54A55BEDcfC4',
        type: 'mined',
        id: 'log_bfd297b0',
        returnValues: [Object],
        event: 'Transfer',
        signature: '0xddf252ad1be2c89b69c2b068fc378daa952ba7f163c4a11628f55a4df523b3ef',
        raw: [Object] } } }
> contract.methods.balanceOf('0x90f8bf6a479f320ead074411a4b0e7944ea8c9c1').call().then(console.log).catch(console.error);
Promise {...}
> 99996