Generates the cryptographic hash (fingerprint) of a local file.

get-file-hash.ts

import * as crypto from "crypto";
import * as fs from "fs";

/**
 * Generates the cryptographic hash (fingerprint) of a local file.
 *
 * @param filePath The path to the file.
 * @param algorithm The hashing algorithm to use (e.g., 'sha256', 'md5').
 *
 * @returns A promise that resolves to the hexadecimal hash string.
 */
export const getFileHash = (
  filePath: string,
  algorithm: string = "sha256",
): Promise<string> => {
  return new Promise((resolve, reject) => {
    // Create a readable stream from the file
    const stream = fs.createReadStream(filePath);
    // Create the hash object
    const hash = crypto.createHash(algorithm);

    // Pipe the stream data to the hash object
    stream.on("data", hash.update);

    // Once the stream ends, finalize the hash and resolve
    stream.on("end", () => {
      resolve(hash.digest("hex"));
    });

    stream.on("error", reject);
    hash.on("error", reject);
  });
};