process-update.js

/**
 * Based heavily on https://github.com/webpack/webpack/blob/
 *  c0afdf9c6abc1dd70707c594e473802a566f7b6e/hot/only-dev-server.js
 * Original copyright Tobias Koppers @sokra (MIT license)
 */

/* global window __webpack_hash__ */

if (!module.hot) {
  throw new Error('[HMR] Hot Module Replacement is disabled.');
}

var hmrDocsUrl = 'https://webpack.js.org/concepts/hot-module-replacement/'; // eslint-disable-line max-len

var lastHash;
var failureStatuses = { abort: 1, fail: 1 };
var applyOptions = {
  ignoreUnaccepted: false,
  ignoreDeclined: true,
  ignoreErrored: true,
  onUnaccepted: function (data) {
    console.warn(
      'Ignored an update to unaccepted module ' + data.chain.join(' -> ')
    );
  },
  onDeclined: function (data) {
    console.warn(
      'Ignored an update to declined module ' + data.chain.join(' -> ')
    );
  },
  onErrored: function (data) {
    console.error(data.error);
    console.warn(
      'Ignored an error while updating module ' +
        data.moduleId +
        ' (' +
        data.type +
        ')'
    );
  },
};

function upToDate(hash) {
  if (hash) lastHash = hash;
  return lastHash == __webpack_hash__;
}

module.exports = function (hash, moduleMap, options) {
  var reload = options.reload;
  if (!upToDate(hash) && module.hot.status() == 'idle') {
    if (options.log) console.log('[HMR] Checking for updates on the server...');
    check();
  }

  function check() {
    var cb = function (err, updatedModules) {
      if (err) return handleError(err);

      if (!updatedModules) {
        if (options.warn) {
          console.warn('[HMR] Cannot find update (Full reload needed)');
          console.warn('[HMR] (Probably because of restarting the server)');
        }
        performReload();
        return null;
      }

      var applyCallback = function (applyErr, renewedModules) {
        if (applyErr) return handleError(applyErr);

        if (!upToDate()) check();

        logUpdates(updatedModules, renewedModules);
      };

      var applyResult = module.hot.apply(applyOptions, applyCallback);
      // webpack 2 promise
      if (applyResult && applyResult.then) {
        // HotModuleReplacement.runtime.js refers to the result as `outdatedModules`
        applyResult.then(function (outdatedModules) {
          applyCallback(null, outdatedModules);
        });
        applyResult.catch(applyCallback);
      }
    };

    var result = module.hot.check(false, cb);
    // webpack 2 promise
    if (result && result.then) {
      result.then(function (updatedModules) {
        cb(null, updatedModules);
      });
      result.catch(cb);
    }
  }

  function logUpdates(updatedModules, renewedModules) {
    var unacceptedModules = updatedModules.filter(function (moduleId) {
      return renewedModules && renewedModules.indexOf(moduleId) < 0;
    });

    if (unacceptedModules.length > 0) {
      if (options.warn) {
        console.warn(
          "[HMR] The following modules couldn't be hot updated: " +
            '(Full reload needed)\n' +
            'This is usually because the modules which have changed ' +
            '(and their parents) do not know how to hot reload themselves. ' +
            'See ' +
            hmrDocsUrl +
            ' for more details.'
        );
        unacceptedModules.forEach(function (moduleId) {
          console.warn('[HMR]  - ' + (moduleMap[moduleId] || moduleId));
        });
      }
      performReload();
      return;
    }

    if (options.log) {
      if (!renewedModules || renewedModules.length === 0) {
        console.log('[HMR] Nothing hot updated.');
      } else {
        console.log('[HMR] Updated modules:');
        renewedModules.forEach(function (moduleId) {
          console.log('[HMR]  - ' + (moduleMap[moduleId] || moduleId));
        });
      }

      if (upToDate()) {
        console.log('[HMR] App is up to date.');
      }
    }
  }

  function handleError(err) {
    if (module.hot.status() in failureStatuses) {
      if (options.warn) {
        console.warn('[HMR] Cannot check for update (Full reload needed)');
        console.warn('[HMR] ' + (err.stack || err.message));
      }
      performReload();
      return;
    }
    if (options.warn) {
      console.warn('[HMR] Update check failed: ' + (err.stack || err.message));
    }
  }

  function performReload() {
    if (reload) {
      if (options.warn) console.warn('[HMR] Reloading page');
      window.location.reload();
    }
  }
};