@toruslabs/metadata-helpers/dist/lib.esm/helpers/hex.js

Helper methods for metadata

import { keccak_256 } from '@noble/hashes/sha3.js';
import { assert } from './assert.js';

// Use native regexes instead of superstruct for maximum performance.
// Pre-compiled regex for maximum performance - avoids recompilation on each call
const HEX_REGEX = /^(?:0x)?[0-9a-f]+$/iu;
const STRICT_HEX_REGEX = /^0x[0-9a-f]+$/iu;
const HEX_ADDRESS_REGEX = /^0x[0-9a-f]{40}$/u;
const HEX_CHECKSUM_ADDRESS_REGEX = /^0x[0-9a-fA-F]{40}$/u;
const isString = value => typeof value === "string";
/**
 * Check if a string is a valid hex string.
 *
 * @param value - The value to check.
 * @returns Whether the value is a valid hex string.
 */
function isHexString(value) {
  return isString(value) && HEX_REGEX.test(value);
}

/**
 * Strictly check if a string is a valid hex string. A valid hex string must
 * start with the "0x"-prefix.
 *
 * @param value - The value to check.
 * @returns Whether the value is a valid hex string.
 */
function isStrictHexString(value) {
  return isString(value) && STRICT_HEX_REGEX.test(value);
}

/**
 * Check if a string is a valid hex address.
 *
 * @param value - The value to check.
 * @returns Whether the value is a valid hex address.
 */
function isHexAddress(value) {
  return isString(value) && HEX_ADDRESS_REGEX.test(value);
}

/**
 * Check if a string is a valid hex checksum address.
 *
 * @param value - The value to check.
 * @returns Whether the value is a valid hex checksum address.
 */
function isHexChecksumAddress(value) {
  return isString(value) && HEX_CHECKSUM_ADDRESS_REGEX.test(value);
}

/**
 * Assert that a value is a valid hex string.
 *
 * @param value - The value to check.
 * @throws If the value is not a valid hex string.
 */
function assertIsHexString(value) {
  assert(isHexString(value), "Value must be a hexadecimal string.");
}

/**
 * Assert that a value is a valid hex string. A valid hex string must start with
 * the "0x"-prefix.
 *
 * @param value - The value to check.
 * @throws If the value is not a valid hex string.
 */
function assertIsStrictHexString(value) {
  assert(isStrictHexString(value), 'Value must be a hexadecimal string, starting with "0x".');
}

/**
 * Encode a passed hex string as an ERC-55 mixed-case checksum address.
 * This is the unmemoized version, primarily used for testing.
 *
 * @param hexAddress - The hex address to encode.
 * @returns The address encoded according to ERC-55.
 * @see https://eips.ethereum.org/EIPS/eip-55
 */
function getChecksumAddress(hexAddress) {
  assert(isHexChecksumAddress(hexAddress), "Invalid hex address.");
  const address = remove0x(hexAddress).toLowerCase();
  const hashBytes = keccak_256(new TextEncoder().encode(address));
  const {
    length
  } = address;
  const result = new Array(length); // Pre-allocate array

  for (let i = 0; i < length; i++) {
    const byteIndex = i >> 1; // Faster than Math.floor(i / 2)
    const nibbleIndex = i & 1; // Faster than i % 2
    const byte = hashBytes[byteIndex];
    const nibble = nibbleIndex === 0 ? byte >> 4 : byte & 0x0f;
    result[i] = nibble >= 8 ? address[i].toUpperCase() : address[i];
  }
  return `0x${result.join("")}`;
}
/**
 * Validate that the passed hex string is a valid ERC-55 mixed-case
 * checksum address.
 *
 * @param possibleChecksum - The hex address to check.
 * @returns True if the address is a checksum address.
 */
function isValidChecksumAddress(possibleChecksum) {
  if (!isHexChecksumAddress(possibleChecksum)) {
    return false;
  }
  return getChecksumAddress(possibleChecksum) === possibleChecksum;
}
/**
 * Validate that the passed prefixed hex string is an all-lowercase
 * hex address, or a valid mixed-case checksum address.
 *
 * @param possibleAddress - Input parameter to check against.
 * @returns Whether or not the input is a valid hex address.
 */
function isValidHexAddress(possibleAddress) {
  return isHexAddress(possibleAddress) || isValidChecksumAddress(possibleAddress);
}

/**
 * Add the `0x`-prefix to a hexadecimal string. If the string already has the
 * prefix, it is returned as-is.
 *
 * @param hexadecimal - The hexadecimal string to add the prefix to.
 * @returns The prefixed hexadecimal string.
 */
function add0x(hexadecimal) {
  if (hexadecimal.startsWith("0x")) {
    return hexadecimal;
  }
  if (hexadecimal.startsWith("0X")) {
    return `0x${hexadecimal.substring(2)}`;
  }
  return `0x${hexadecimal}`;
}

/**
 * Remove the `0x`-prefix from a hexadecimal string. If the string doesn't have
 * the prefix, it is returned as-is.
 *
 * @param hexadecimal - The hexadecimal string to remove the prefix from.
 * @returns The un-prefixed hexadecimal string.
 */
function remove0x(hexadecimal) {
  if (hexadecimal.startsWith("0x") || hexadecimal.startsWith("0X")) {
    return hexadecimal.substring(2);
  }
  return hexadecimal;
}

export { add0x, assertIsHexString, assertIsStrictHexString, getChecksumAddress, isHexAddress, isHexChecksumAddress, isHexString, isStrictHexString, isValidChecksumAddress, isValidHexAddress, remove0x };