以太坊錢包開發系列4 - 傳送Token(代幣）

contract ERC20Interface {

string public constant name = "Token Name";
string public constant symbol = "SYM";
uint8 public constant decimals = 0; 

function totalSupply() public constant returns (uint);

function balanceOf(address tokenOwner) public constant returns (uint balance);

function allowance(address tokenOwner, address spender) public constant returns (uint remaining);
function approve(address spender, uint tokens) public returns (bool success);

function transfer(address to, uint tokens) public returns (bool success);
function transferFrom(address from, address to, uint tokens) public returns (bool success);


event Transfer(address indexed from, address indexed to, uint tokens);
event Approval(address indexed tokenOwner, address indexed spender, uint tokens);
}

[
...
{
"constant": true,
"inputs": [],
"name": "totalSupply",
"outputs": [
{
"name": "",
"type": "uint256"
}
],
"payable": false,
"stateMutability": "view",
"type": "function"
},
{
"constant": true,
"inputs": [
{
"name": "tokenOwner",
"type": "address"
}
],
"name": "balanceOf",
"outputs": [
{
"name": "balance",
"type": "uint256"
}
],
"payable": false,
"stateMutability": "view",
"type": "function"
},
...
]

var abi = [...];
var addr = "0x..."; 
var contract = new ethers.Contract(address, abi, provider);

<tr>
<th>TT Token:</th>
<td>
<input type="text" readonly="readonly" class="readonly" id="wallet-token-balance" value="0.0" /></div>
</td>
</tr>

 var tokenBalance = $('#wallet-token-balance');
 // 直接呼叫合約方法
contract.balanceOf(activeWallet.address).then(function(balance){
tokenBalance.val(balance);
});

<h3>轉移代幣:</h3>
<table>
<tr>
<th>傳送至:</th>
<td><input type="text" placeholder="(target address)" id="wallet-token-send-target-address" /></td>
</tr>
<tr>
<th>金額:</th>
<td><input type="text" placeholder="(amount)" id="wallet-token-send-amount" /></td>
</tr>
<tr>
<td> </td>
<td>
<div id="wallet-token-submit-send" class="submit disable">傳送</div>
</td>
</tr>
</table>

var inputTargetAddress = $('#wallet-token-send-target-address');
var inputAmount = $('#wallet-token-send-amount');
var submit = $('#wallet-token-submit-send');

var targetAddress = ethers.utils.getAddress(inputTargetAddress.val());
var amount = inputAmount.val();

submit.click(function() {
// 先計算transfer 需要的gas 消耗量，這一步有預設值，非必須。
contract.estimate.transfer(targetAddress, amount)
.then(function(gas) {

// 必須關聯一個有過簽名錢包物件
let contractWithSigner = contract.connect(activeWallet); 

//發起交易，前面2個引數是函式的引數，第3個是交易引數
contractWithSigner.transfer(targetAddress, amount, {
gasLimit: gas,
// 偷懶，直接是用 2gwei
gasPrice: ethers.utils.parseUnits("2", "gwei"),
}).then(function(tx) {
console.log(tx);
// 介紹重新整理上面的Token餘額，重置輸入框
});
});
}