vaadin-development-mode-detector.html

<script>
(function() {
  const DEV_MODE_CODE_REGEXP =
    /\/\*\*\s+vaadin-dev-mode:start([\s\S]*)vaadin-dev-mode:end\s+\*\*\//i;

  const FlowClients = window.Vaadin && window.Vaadin.Flow && window.Vaadin.Flow.clients;

  function isMinified() {
    function test() {
      /** vaadin-dev-mode:start
      return false;
      vaadin-dev-mode:end **/
      return true;
    }
    return uncommentAndRun(test);
  }

  function isDevelopmentMode() {
    try {
      if (isForceDevelopmentMode()) {
        return true;
      }

      if (!isLocalhost()) {
        return false;
      }

      if (FlowClients) {
        return !isFlowProductionMode();
      }

      return !isMinified();
    } catch (e) {
      // Some error in this code, assume production so no further actions will be taken
      return false;
    }
  }

  function isForcedDevelopmentMode() {
    return localStorage.getItem("vaadin.developmentmode.force");
  }

  function isLocalhost() {
    return (["localhost","127.0.0.1"].indexOf(window.location.hostname) >= 0);
  }

  function isFlowProductionMode() {
    if (FlowClients) {
      const productionModeApps = Object.keys(FlowClients)
        .map(key => FlowClients[key])
        .filter(client => client.productionMode);
      if (productionModeApps.length > 0) {
        return true;
      }
    }
    return false;
  }

  function uncommentAndRun(callback, args) {
    if (typeof callback !== 'function') {
      return;
    }

    const match = DEV_MODE_CODE_REGEXP.exec(callback.toString());
    if (match) {
      try {
        // requires CSP: script-src 'unsafe-eval'
        callback = new Function(match[1]);
      } catch (e) {
        // eat the exception
        console.log('vaadin-development-mode-detector: uncommentAndRun() failed', e)
      }
    }

    return callback(args);
  }

  /**
   * @namespace Vaadin
   */
  window.Vaadin = window.Vaadin || {};

  // A guard against polymer-modulizer removing the window.Vaadin
  // initialization above.
  window['Vaadin'] = window['Vaadin'] || {};

  /**
   * Inspects the source code of the given `callback` function for
   * specially-marked _commented_ code. If such commented code is found in the
   * callback source, uncomments and runs that code instead of the callback
   * itself. Otherwise runs the callback as is.
   *
   * The optional arguments are passed into the callback / uncommented code,
   * the result is returned.
   *
   * See the `isMinified()` function source code in this file for an example.
   *
   * @memberof Vaadin
   */
  window.Vaadin.runIfDevelopmentMode = function(callback, args) {
    if (window.Vaadin.developmentMode) {
      return uncommentAndRun(callback, args);
    }
  };

  if (window.Vaadin.developmentMode === undefined) {
    window.Vaadin.developmentMode = isDevelopmentMode();
  }
})();
</script>