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
)

We should notice that, if tokenX or tokenY is chain token (like ETH on ethereum or BNB on bsc), we should specify one field in params to indicate sdk collecting in form of Chain Token or collecting in form of Wrapped Chain Token (like WETH on ethereum or WBNB on bsc).

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 collecting in form of Chain Token. In the sdk version 1.2.* or later, you have two ways to indicate sdk.

The first way is as before, specifing strictERC20Token field. The second way is specifing strictERC20Token as undefined and specifying the corresponding token in this param as WETH or ETH.

3. estimate gas (optional)

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

const gasLimit = await collectLimitOrderCalling.estimateGas(options)

4. 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).