Does approve take time to be confirmed, and how to deal with this in BSC?

Hi I am doing BSC DApp using web3 with react. I am very new to this field.

I found after call approve, the transfer(or zapInToken in my case) will not be successful with complaining not enough allowance. So I added wait allowance to be present for 10s, but it seems in many times(50% chance) after 10s the allowance still not present. Please check the below code for more information.

Theoretically, approve will generate a transaction and the time to be present depends. If it is the case, Is it a standard pattern to approve, wait for allowance and transfer?

Thank you!

const bepContract = getContract(getAddress(from), erc20ABI, library, account)  const tx = await bepContract.approve(getAddress(contracts.zap), weiAmount)  if (!tx) {      throw new Error('Failed to approve transaction')  }  await waitAllowance(bepContract, account, getAddress(contracts.zap), weiAmount, 10) // <-- and it will stuck here in most time, the code waits for the allowance is present  await getZapContract().zapInToken(getAddress(from), weiAmount, getAddress(to)).then(logInfo).catch(logError)  

And the waitAllowance is like below

const waitAllowance = async (    contract: Contract,    account: string,    to: string,    allowanceNeeded: string,    timesLeft: number  ): Promise<void> => {    if (timesLeft > 1) {      const currentAllowance = await contract.allowance(account, to)      // console.log(`I want ${allowanceNeeded}, and current is ${currentAllowance} `)      const needed = new BigNumber(allowanceNeeded)      const current = new BigNumber(currentAllowance.toString())      if (current.isGreaterThanOrEqualTo(needed)) {        return      }      await new Promise((res) => setTimeout(res, 1000))      await waitAllowance(contract, account, to, allowanceNeeded, timesLeft - 1)    }    throw new Error('wait allowance failed for many times.')  }  

https://stackoverflow.com/questions/67377356/does-approve-take-time-to-be-confirmed-and-how-to-deal-with-this-in-bsc May 04, 2021 at 08:31AM