How to use the tiny-secp256k1.pointMultiply function in tiny-secp256k1

function stealthDualReceive (d, r, eG) {
  const eQ = ecc.pointMultiply(eG, d) // shared secret
  const c = bitcoin.crypto.sha256(eQ)
  const rc = ecc.privateAdd(r, c)
  const v = bitcoin.ECPair.fromPrivateKey(rc)

  return v
}

function stealthDualSend (e, R, Q) {
  const eQ = ecc.pointMultiply(Q, e) // shared secret
  const c = bitcoin.crypto.sha256(eQ)
  const Rc = ecc.pointAddScalar(R, c)
  const vG = bitcoin.ECPair.fromPublicKey(Rc)

  return vG
}

function stealthSend (e, Q) {
  const eQ = ecc.pointMultiply(Q, e, true) // shared secret
  const c = bitcoin.crypto.sha256(eQ)
  const Qc = ecc.pointAddScalar(Q, c)
  const vG = bitcoin.ECPair.fromPublicKey(Qc)

  return vG
}

function stealthReceive (d, eG) {
  const eQ = ecc.pointMultiply(eG, d) // shared secret
  const c = bitcoin.crypto.sha256(eQ)
  const dc = ecc.privateAdd(d, c)
  const v = bitcoin.ECPair.fromPrivateKey(dc)

  return v
}

function stealthRecoverLeaked (v, e, Q) {
  const eQ = ecc.pointMultiply(Q, e) // shared secret
  const c = bitcoin.crypto.sha256(eQ)
  const vc = ecc.privateSub(v, c)
  const d = bitcoin.ECPair.fromPrivateKey(vc)

  return d
}

function stealthDualScan (d, R, eG) {
  const eQ = ecc.pointMultiply(eG, d) // shared secret
  const c = bitcoin.crypto.sha256(eQ)
  const Rc = ecc.pointAddScalar(R, c)
  const vG = bitcoin.ECPair.fromPublicKey(Rc)

  return vG
}