Error: Returned error: The execution failed due to an exception. @ web3.eth.estimateGas

Question

I am having problem using bignumber.js with web3:

const sender = '0xss';
const recipient = '0xxx';
const amount = 1000; // have to use Bignumber for more than 1000
const decimals = 18;
const amountHex = web3.utils.toHex(new BigNumber(`${amount}e+${decimals}`));
const count = await web3.eth.getTransactionCount(sender);
const data = contract.methods.transfer(recipient, amountHex).encodeABI();
const estimateGas = await web3.eth.estimateGas({
    from: sender,
    nonce: '0x' + count.toString(16),
    to: '0xff',
    data
});

I get error at estimateGas :

Error: Returned error: The execution failed due to an exception.

Answer 1

Web3.js v0.x relies on BigNumber.

Web3.js v1.x relies on BN.

The fact that you're calling web3.utils.toHex implies that you're using Web3.js v1.x.

Also note that you don't need your amount as a hex string; you can use either an integer or a string which represents an integer (which can be in either decimal format or hexadecimal format) or a BN instance.

So in short, instead of this:

const amountHex = web3.utils.toHex(new BigNumber(`${amount}e+${decimals}`));

You can use either one of the following:

const amount = `${amount}e+${decimals}`;
const amount = web3.utils.toBN(`${amount}e+${decimals}`);

You may also be tempted to use this:

const amount = Number(`${amount}e+${decimals}`);

However, since the value represented by this string is most likely larger than Number.MAX_SAFE_INTEGER, you should avoid this option as it will potentially yield an innaccurate value.