That's what i used to calculate the vote value.
P.S: it's just estimate

export const calculateVoteValue = (
  vests,
  recentClaims,
  rewardBalance,
  vp = 10000,
  weight = 10000,
) => {
  const vestingShares = parseInt(vests * 1e6, 10);
  const power = vp * weight / 10000 / 50;
  const rshares = power * vestingShares / 10000;
  return rshares / recentClaims * rewardBalance/2;
};