@metaphi/airwallet-api/lib/utils.js

Metaphi Airwallet API to add whitelabel, non-custodial wallets to dApps

// Source: https://github.com/MetaMask/eth-sig-util/blob/8f5a90bed37e6891fe4e9ab98a8cd4f62188d5c4/src/utils.ts
import {
  addHexPrefix,
  bufferToInt,
  fromSigned,
  toUnsigned,
} from "ethereumjs-util";
import { intToHex, isHexString, stripHexPrefix } from "ethjs-util";

/**
 * Pads the front of the given hex string with zeroes until it reaches the
 * target length. If the input string is already longer than or equal to the
 * target length, it is returned unmodified.
 *
 * If the input string is "0x"-prefixed or not a hex string, an error will be
 * thrown.
 *
 * @param hexString - The hexadecimal string to pad with zeroes.
 * @param targetLength - The target length of the hexadecimal string.
 * @returns The input string front-padded with zeroes, or the original string
 * if it was already greater than or equal to to the target length.
 */
export function padWithZeroes(hexString, targetLength) {
  if (hexString !== "" && !/^[a-f0-9]+$/iu.test(hexString)) {
    throw new Error(
      `Expected an unprefixed hex string. Received: ${hexString}`
    );
  }

  if (targetLength < 0) {
    throw new Error(
      `Expected a non-negative integer target length. Received: ${targetLength}`
    );
  }

  return String.prototype.padStart.call(hexString, targetLength, "0");
}

/**
 * Concatenate an extended ECDSA signature into a single '0x'-prefixed hex string.
 *
 * @param v - The 'v' portion of the signature.
 * @param r - The 'r' portion of the signature.
 * @param s - The 's' portion of the signature.
 * @returns The concatenated ECDSA signature as a '0x'-prefixed string.
 */
export function concatSig(v, r, s) {
  const rSig = fromSigned(r);
  const sSig = fromSigned(s);
  const vSig = bufferToInt(v);
  const rStr = padWithZeroes(toUnsigned(rSig).toString("hex"), 64);
  const sStr = padWithZeroes(toUnsigned(sSig).toString("hex"), 64);
  const vStr = stripHexPrefix(intToHex(vSig));
  return addHexPrefix(rStr.concat(sStr, vStr));
}


// Source: https://stackoverflow.com/a/2117523/3545099
export function uuidv4() {
  return ([1e7] + -1e3 + -4e3 + -8e3 + -1e11).replace(/[018]/g, (c) =>
    (
      c ^
      (crypto.getRandomValues(new Uint8Array(1))[0] & (15 >> (c / 4)))
    ).toString(16),
  );
}

export function getMetaphiIframeDomain (env) {
  if (env === 'development') {
    return 'http://localhost:8080'
  }

  return 'https://www.metaphi.xyz'
}