ethereumjs-util @types/bn.js issue

index.ts

import { bufferToHex, ecrecover, fromRpcSig, hashPersonalMessage, publicToAddress } from 'ethereumjs-util'

export function signatureIsValid(address: string, message: string, signature: string): boolean {
  const msgHash = hashPersonalMessage(Buffer.from(message))

  const signatureParams = fromRpcSig(signature)
  const publicKey = ecrecover(
    msgHash,
    signatureParams.v,
    signatureParams.r,
    signatureParams.s,
  )
  const addressBuffer = publicToAddress(publicKey)
  const addressVerified = bufferToHex(addressBuffer)

  return addressVerified === address
}

const signedMessage = {
  "address": "0xbe7d20a0f75dbccb82efe6ae3af1768e5e83d0b8",
  "msg": "Secret Message",
  "sig": "0x5e06a683754daa113774b42a1c3fd1f038b95e82eea918d404bab8d229df4ed06a4f5497aa9969a55aa559b97a48655d99b08c6992134c2d5d65b3becb11cf2b1c",
  "version": "3",
  "signer": "MEW"
}


console.log(signatureIsValid(signedMessage.address, signedMessage.msg, signedMessage.sig))

package.json

{
  "name": "example-ethereumjs-util-issue",
  "version": "1.0.0",
  "description": "",
  "main": "index.js",
  "scripts": {
    "build": "tsc"
  },
  "keywords": [],
  "author": "",
  "license": "ISC",
  "devDependencies": {
    "@types/node": "12.0.2",
    "typescript": "3.4.5"
  },
  "dependencies": {
    "ethereumjs-util": "6.1.0"
  }
}

tsconfig.json

{
  "compilerOptions": {
    "target": "ES2019",
    "module": "commonjs",
    "sourceMap": true,
    "strict": true,
    "esModuleInterop": true
  }
}