asset-hash/lib/index.esm.js

Very fast asset hashing function for using e.g. during front-end deployments.

/*! asset-hash v4.1.0 by Sebastian Werner <s.werner@sebastian-software.de> */
import 'core-js/modules/es.error.cause.js';
import { createReadStream } from 'fs';
import { extname } from 'path';
import { createHash } from 'crypto';
import xxhash from 'xxhash-wasm';
import { fingerprint32, fingerprint64 } from 'farmhash';

function baseEncodeFactory(charset) {
  const radix = BigInt(charset.length);

  const decode = str => {
    let result = BigInt(0);

    for (const chr of str) {
      const index = BigInt(charset.indexOf(chr));
      result = radix * result + index;
    }

    return result;
  };

  const encode = (number, maxLength = Infinity) => {
    let result = "";

    while (number > 0) {
      const mod = number % radix;
      result = charset[Number(mod)] + result;
      number = (number - mod) / radix;

      if (result.length === maxLength) {
        return result;
      }
    }

    return result || `0`;
  };

  return {
    decode,
    encode
  };
}
const baseEncoder = {
  base26: baseEncodeFactory("abcdefghijklmnopqrstuvwxyz"),
  base32: baseEncodeFactory("123456789abcdefghjkmnpqrstuvwxyz"),
  // no 0lio
  base36: baseEncodeFactory("0123456789abcdefghijklmnopqrstuvwxyz"),
  base49: baseEncodeFactory("abcdefghijkmnopqrstuvwxyzABCDEFGHJKLMNPQRSTUVWXYZ"),
  // no lIO
  base52: baseEncodeFactory("abcdefghijklmnopqrstuvwxyzABCDEFGHIJKLMNOPQRSTUVWXYZ"),
  base58: baseEncodeFactory("123456789abcdefghijkmnopqrstuvwxyzABCDEFGHJKLMNPQRSTUVWXYZ"),
  // no 0lIO
  base62: baseEncodeFactory("0123456789abcdefghijklmnopqrstuvwxyzABCDEFGHIJKLMNOPQRSTUVWXYZ")
};
function computeDigest(rawDigest, options = {}) {
  let output = null;
  const {
    encoding,
    maxLength
  } = options;
  const rawIsNumber = typeof rawDigest === "number" || typeof rawDigest === "bigint";
  const rawIsBuffer = rawDigest instanceof Buffer; // Fast-path for number => hex

  if (rawIsNumber && encoding === "hex") {
    output = rawDigest.toString(16);
  } else {
    if (encoding === "base26" || encoding === "base32" || encoding === "base36" || encoding === "base49" || encoding === "base52" || encoding === "base58" || encoding === "base62") {
      const valueAsBigInt = rawDigest instanceof Buffer ? BigInt(`0x${rawDigest.toString("hex")}`) : typeof rawDigest === "number" ? BigInt(rawDigest) : BigInt(rawDigest);
      return baseEncoder[encoding].encode(valueAsBigInt, maxLength);
    }

    const valueAsBuffer = rawIsBuffer ? rawDigest : Buffer.from(rawDigest.toString());
    output = valueAsBuffer.toString(encoding);
  }

  return maxLength != null ? output.slice(0, maxLength) : output;
}

let xxHashInstance;
let hasherReady = false;
async function initHashClasses() {
  if (hasherReady) {
    return;
  } // Allow failing initialization for platforms < Node v16


  try {
    xxHashInstance = await xxhash();
  } catch {}

  hasherReady = true;
}

/**
 * Make Node.js crypto hash signature compatible to Hash
 */
function cryptoEnvelope(hash) {
  const envelopeHash = {
    update: input => {
      hash.update(input);
      return envelopeHash;
    },
    digest: () => hash.digest()
  };
  return envelopeHash;
}

function farmhashEnvelope(hash) {
  const data = [];
  const envelopeHash = {
    update: input => {
      data.push(input);
      return envelopeHash;
    },
    digest: () => {
      const stringOrNumber = hash(Buffer.concat(data));
      return BigInt(stringOrNumber);
    }
  };
  return envelopeHash;
}
/**
 * Creates hasher instance
 */


function createHasher(algorithm) {
  if (!hasherReady) {
    throw new Error("Hasher was not correctly initialized. Call `await initHashClasses()` first.");
  }

  let hasher;

  if (algorithm === "xxhash32" || algorithm === "xxhash64") {
    if (!xxHashInstance) {
      throw new Error("Invalid xxhash WASM instance!");
    }

    hasher = algorithm === "xxhash32" ? xxHashInstance.create32() : xxHashInstance.create64();
  } else if (algorithm === "farmhash32" || algorithm === "farmhash64") {
    hasher = farmhashEnvelope(algorithm === "farmhash32" ? fingerprint32 : fingerprint64);
  } else {
    hasher = cryptoEnvelope(createHash(algorithm));
  }

  return hasher;
}

const NODE_MAJOR_VERSION = parseInt(process.versions.node.split('.')[0], 10);
const NODE_SUPPORTS_BIGINT_SINCE = 16;
const DEFAULT_ALGORITHM = NODE_MAJOR_VERSION < NODE_SUPPORTS_BIGINT_SINCE ? "farmhash64" : "xxhash64";
const DEFAULT_ENCODING = "base52";
const DEFAULT_MAX_LENGTH = 8;
class Hasher {
  algorithm = DEFAULT_ALGORITHM;
  encoding = DEFAULT_ENCODING;
  maxLength = Infinity;

  constructor(options = {}) {
    if (options.algorithm) {
      this.algorithm = options.algorithm;
    }

    if (options.encoding) {
      this.encoding = options.encoding;
    }

    if (options.maxLength) {
      this.maxLength = options.maxLength;
    }

    this.hasher = createHasher(this.algorithm);
  }

  update(data) {
    const buffer = data instanceof Buffer ? data : Buffer.from(data.toString(), "utf-8");
    this.hasher.update(buffer);
    return this;
  }

  digest(encoding, maxLength) {
    return computeDigest(this.hasher.digest(), {
      encoding: encoding || this.encoding,
      maxLength: maxLength || this.maxLength
    });
  }

}
/**
 * Get hash from file
 *
 * @param fileName Filename of file to hash
 */

function getHash(fileName, options) {
  const {
    algorithm,
    encoding,
    maxLength
  } = options || {};
  return new Promise(async (resolve, reject) => {
    try {
      await initHashClasses();
      const hasher = createHasher(algorithm || DEFAULT_ALGORITHM);
      createReadStream(fileName).on("data", data => {
        hasher.update(data);
      }).on("error", error => {
        reject(error);
      }).on("end", () => {
        try {
          const digest = computeDigest(hasher.digest(), {
            encoding: encoding || DEFAULT_ENCODING,
            maxLength: maxLength || DEFAULT_MAX_LENGTH
          });
          digest ? resolve(digest) : reject(new Error("Unexpected error while generating digest!"));
        } catch (error) {
          reject(error);
        }
      });
    } catch (error) {
      reject(error);
    }
  });
}
/**
 * Get new filename based upon hash and extension of file
 *
 * @param fileName Filename of file to hash
 */

async function getHashedName(fileName, options) {
  const hashed = await getHash(fileName, options);
  const extension = extname(fileName);
  return hashed + extension;
}

export { DEFAULT_ALGORITHM, DEFAULT_ENCODING, DEFAULT_MAX_LENGTH, Hasher, getHash, getHashedName, initHashClasses };
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