@metamask/utils/dist/hex.mjs

Various JavaScript/TypeScript utilities of wide relevance to the MetaMask codebase

import { is, pattern, string } from "@metamask/superstruct";
import { keccak_256 as keccak256 } from "@noble/hashes/sha3";
import { assert } from "./assert.mjs";
import { bytesToHex } from "./bytes.mjs";
export const HexStruct = pattern(string(), /^(?:0x)?[0-9a-f]+$/iu);
export const StrictHexStruct = pattern(string(), /^0x[0-9a-f]+$/iu);
export const HexAddressStruct = pattern(string(), /^0x[0-9a-f]{40}$/u);
export const HexChecksumAddressStruct = pattern(string(), /^0x[0-9a-fA-F]{40}$/u);
/**
 * Check if a string is a valid hex string.
 *
 * @param value - The value to check.
 * @returns Whether the value is a valid hex string.
 */
export function isHexString(value) {
    return is(value, HexStruct);
}
/**
 * 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.
 */
export function isStrictHexString(value) {
    return is(value, StrictHexStruct);
}
/**
 * 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.
 */
export 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.
 */
export function assertIsStrictHexString(value) {
    assert(isStrictHexString(value), 'Value must be a hexadecimal string, starting with "0x".');
}
/**
 * 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.
 */
export function isValidHexAddress(possibleAddress) {
    return (is(possibleAddress, HexAddressStruct) ||
        isValidChecksumAddress(possibleAddress));
}
/**
 * Encode a passed hex string as an ERC-55 mixed-case checksum address.
 *
 * @param address - The hex address to encode.
 * @returns The address encoded according to ERC-55.
 * @see https://eips.ethereum.org/EIPS/eip-55
 */
export function getChecksumAddress(address) {
    assert(is(address, HexChecksumAddressStruct), 'Invalid hex address.');
    const unPrefixed = remove0x(address.toLowerCase());
    const unPrefixedHash = remove0x(bytesToHex(keccak256(unPrefixed)));
    return `0x${unPrefixed
        .split('')
        .map((character, nibbleIndex) => {
        const hashCharacter = unPrefixedHash[nibbleIndex];
        assert(is(hashCharacter, string()), 'Hash shorter than address.');
        return parseInt(hashCharacter, 16) > 7
            ? character.toUpperCase()
            : character;
    })
        .join('')}`;
}
/**
 * Validate that the passed hex string is a valid ERC-55 mixed-case
 * checksum address.
 *
 * @param possibleChecksum - The hex address to check.
 * @returns True if the address is a checksum address.
 */
export function isValidChecksumAddress(possibleChecksum) {
    if (!is(possibleChecksum, HexChecksumAddressStruct)) {
        return false;
    }
    return getChecksumAddress(possibleChecksum) === possibleChecksum;
}
/**
 * Add the `0x`-prefix to a hexadecimal string. If the string already has the
 * prefix, it is returned as-is.
 *
 * @param hexadecimal - The hexadecimal string to add the prefix to.
 * @returns The prefixed hexadecimal string.
 */
export function add0x(hexadecimal) {
    if (hexadecimal.startsWith('0x')) {
        return hexadecimal;
    }
    if (hexadecimal.startsWith('0X')) {
        return `0x${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.
 */
export function remove0x(hexadecimal) {
    if (hexadecimal.startsWith('0x') || hexadecimal.startsWith('0X')) {
        return hexadecimal.substring(2);
    }
    return hexadecimal;
}
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