collect limit order

here, we provide a simple example to fetch limit orders of iZiSwap from an user’s address, and select one of them to collect

The full example code of this chapter can be spotted here.

1. fetch limit orders

const chain:BaseChain = initialChainTable[ChainId.BSC]
const rpc = 'https://bsc-dataseed2.defibit.io/'
const web3 = new Web3(new Web3.providers.HttpProvider(rpc))
const account =  web3.eth.accounts.privateKeyToAccount(privateKey)

const limitOrderAddress = '0x9Bf8399c9f5b777cbA2052F83E213ff59e51612B'
const limitOrderManager = getLimitOrderManagerContract(limitOrderAddress, web3)


const testAAddress = '0xCFD8A067e1fa03474e79Be646c5f6b6A27847399'
const testBAddress = '0xAD1F11FBB288Cd13819cCB9397E59FAAB4Cdc16F'

const testA = await fetchToken(testAAddress, chain, web3)
const testB = await fetchToken(testBAddress, chain, web3)
const fee = 2000 // 2000 means 0.2%

// fetch limit order
const {activeOrders, deactiveOrders} = await fetchLimitOrderOfAccount(
    chain, web3, limitOrderManager, '0xD0B1c02E8A6CA05c7737A3F4a0EEDe075fa4920C', [testA]
)

the code above is nearly the same as fetch limit order, you can view more detailed explains though this link

2. select an order to collect and get calling

first, select an order or your own

const activeOrderAt2 = activeOrders[2]

second, get calling of decrease the limit order

const orderIdx = activeOrderAt2.idx
const gasPrice = '5000000000'
const params: CollectLimOrderParam = {
    orderIdx,
    tokenX: activeOrderAt2.tokenX,
    tokenY: activeOrderAt2.tokenY,
    collectDecAmount: activeOrderAt2.sellingDec,
    collectEarnAmount: '1'
}
// dec limit order of orderIdx
const {collectLimitOrderCalling, options} = getCollectLimitOrderCall(
    limitOrderManager,
    account.address,
    chain,
    params,
    gasPrice
)

Notice: if tokenX or tokenY is chain gas token (like ETH on ethereum or BNB on bsc), and you want to collect tokenX or tokenY in form of native or wrapped-native token, you can refer to following section

3. collect native or wrapped native token

In the sdk version 1.2.* or later,

If you want to collect in form of native token(like BNB on bsc or ETH on ethereum …), you should replace define of params in section 2 with following code (here we are working on bsc chain), and fill strictERC20Token of params as undefined by default. And the options calculated in section 2 will contain corresponding msg.value.

const BNBAddress = '0xbb4CdB9CBd36B01bD1cBaEBF2De08d9173bc095c';
const params: CollectLimOrderParam = {
    orderIdx,
    tokenX: activeOrderAt2.tokenX,
    tokenY: activeOrderAt2.tokenY,
    collectDecAmount: activeOrderAt2.sellingDec,
    collectEarnAmount: '1'
}
if (params.tokenX.address.toLowerCase() === BNBAddress.toLowerCase()) {
    params.tokenX.symbol = 'BNB';
}
if (params.tokenY.address.toLowerCase() === BNBAddress.toLowerCase()) {
    params.tokenY.symbol = 'BNB';
}

If you want to collect in form of wrapped-native token(like WBNB on bsc or WETH on ethereum …), you should replace define of params in section 2 with following code (here we are working on bsc chain), and fill strictERC20Token of params as undefined which is the default value for that field.

const BNBAddress = '0xbb4CdB9CBd36B01bD1cBaEBF2De08d9173bc095c';
const params: CollectLimOrderParam = {
    orderIdx,
    tokenX: activeOrderAt2.tokenX,
    tokenY: activeOrderAt2.tokenY,
    collectDecAmount: activeOrderAt2.sellingDec,
    collectEarnAmount: '1'
}
if (params.tokenX.address.toLowerCase() === BNBAddress.toLowerCase()) {
    params.tokenX.symbol = 'WBNB'; // only difference with above code
}
if (params.tokenY.address.toLowerCase() === BNBAddress.toLowerCase()) {
    params.tokenY.symbol = 'WBNB'; // only difference with above code
}

we can see that, the only difference of collection native token and wrapped-native token is symbol field of params.tokenX or params.tokenY.

In the sdk version 1.1.* or before, one should specify a field named strictERC20Token to indicate that. true for collecting token in form of Wrapped Chain Token, false for paying in form of Chain Token. But we suggest you to upgrade your sdk to latest version.

4. estimate gas (optional)

of course you can skip this step if you don’t want to limit gas.

const gasLimit = await collectLimitOrderCalling.estimateGas(options)

5. finally, send transaction!

for metamask or other explorer’s wallet provider, you can easily write

await collectLimitOrderCalling.send({...options, gas: Number(gasLimit)})

otherwise, if you run codes in console, you could use following code

const signedTx = await web3.eth.accounts.signTransaction(
    {
        ...options,
        to: limitOrderAddress,
        data: collectLimitOrderCalling.encodeABI(),
        gas: new BigNumber(Number(gasLimit) * 1.1).toFixed(0, 2),
    },
    privateKey
)
// nonce += 1;
const tx = await web3.eth.sendSignedTransaction(signedTx.rawTransaction);

after this step, we have successfully collect a limit order (if no revert occurred).