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import { BigNumber } from '@ethersproject/bignumber'
import { getAddress } from '@ethersproject/address'
import { remove0x, add0x } from './hex-strings'
/**
* Converts an ethers BigNumber into an equivalent Ethereum address representation.
*
* @param bn BigNumber to convert to an address.
* @return BigNumber converted to an address, represented as a hex string.
*/
export const bnToAddress = (bn: BigNumber | number): string => {
// Coerce numbers into a BigNumber.
bn = BigNumber.from(bn)
// Negative numbers are converted to addresses by adding MAX_ADDRESS + 1.
// TODO: Explain this in more detail, it's basically just matching the behavior of doing
// addr(uint256(addr) - some_number) in Solidity where some_number > uint256(addr).
if (bn.isNegative()) {
bn = BigNumber.from('0xFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFF')
.add(bn)
.add(1)
}
// Convert to a hex string
let addr = bn.toHexString()
// Remove leading 0x so we can mutate the address a bit
addr = remove0x(addr)
// Make sure it's 40 characters (= 20 bytes)
addr = addr.padStart(40, '0')
// Only take the last 40 characters (= 20 bytes)
addr = addr.slice(addr.length - 40, addr.length)
// Add 0x again
addr = add0x(addr)
// Convert into a checksummed address
addr = getAddress(addr)
return addr
}