interlockjs/interlock

import crypto from "crypto";
import { assign } from "lodash";

import { pluggable } from "pluggable";


/**
 * Calculate the bundle's hash by invoking `update` with data from the bundle.
 * `update` should be called with string data only.
 *
 * @param  {Function} update  Updates the ongoing computation of bundle hash.
 * @param  {Object}   bundle  The bundle object.
 */
const updateBundleHash = pluggable(function updateBundleHash (update, bundle) {
  update(JSON.stringify(bundle.moduleHashes), "utf-8");
  update(JSON.stringify(!!bundle.entry), "utf-8");
  update(JSON.stringify(!!bundle.includeRuntime), "utf-8");
});

/**
 * Given an otherwise prepared bundle, generate a hash for that bundle and resolve
 * to that same bundle with a new `hash` property.
 *
 * @param   {Object} bundle  Unhashed bundle.
 *
 * @returns {Object}         Bundle plus new `hash` property, a 40-character SHA1
 *                           that uniquely identifies the bundle.
 */
function hashBundle (bundle) {
  // Node v0.10.x cannot re-use crypto instances after digest is called.
  bundle.setHash = crypto.createHash("sha1")
    .update(JSON.stringify(bundle.moduleHashes), "utf-8")
    .digest("hex");

  const shasum = crypto.createHash("sha1");
  const update = shasum.update.bind(shasum);

  return this.updateBundleHash(update, bundle)
    .then(() => assign({}, bundle, {
      hash: shasum.digest("base64")
        .replace(/\//g, "_")
        .replace(/\+/g, "-")
        .replace(/=+$/, "")
    }));
}

export default pluggable(hashBundle, { updateBundleHash });