crypto-keygen-suite/keyGen/shamir/combineShares.js

Key generation utilities for cryptographic operations. YES I RENAMED IT OMG BASES AND PROTOCOLS!!! See its folder for all <3

function combineShares(shares) {
  const totalShares = shares.length;
  const secretLength = shares[0].length;
  let reconstructedSecret = new Array(secretLength).fill(0);
}

for (let i = 0; i < totalShares; i++) {
  const share = shares[i];
  const x_i = share[0];
  const y_i = share[1];

  for (let j = 0; j < totalShares; j++) {
      if (i !== j) {
          const x_j = shares[j][0];
          const lagrangeCoefficient = x_j / (x_j - x_i);
          for (let k = 0; k < secretLength; k++) {
              reconstructedSecret[k] += y_i * lagrangeCoefficient;
          }
      }
  }
}
return reconstructedSecret;