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The spiderLinks function is supposed to be asynchronous, but it seems that the callback will be executed synchronously in case utilities.getPageLinks(currentUrl, body) returns an empty array.

When I start the API and web server, both start without issue. However, when I navigate a browser to localhost:300, the terminal responds with "TypeError: loadPropsOnServer is not a function."

When I remove .default from require('async-props').default and run both the API and web server, then navigate the browser to that page, the page hangs and here is a response in the web server terminal:

Warning: React.createElement: type should not be null, undefined, boolean, or number. It should be a string (for DOM elements) or a ReactClass (for composite components).

Any clues?

Chapter 10 - Service Registry
unregisterService listener is asynchronous
Process Event: 'exit' listener must be synchronous

All examples are missing the appropriate code of the [ authsrv-plugin-logout ] package.

The promisify function (Chapter04/01_promisify.js) contains a reference to the arguments variable in the callback which happens to be an arrow function (with lexical arguments).

Please find attached a test which demonstrates the problem.

Thank you.

test.js.txt

The createProxy function (Chapter03/09_proxy_c) has a reference to this, in the patched version of the hello method, which happens to be an arrow function (with lexical this).

Please find a test attached to demonstrate the problem. Thank you.

test.js.txt

For the section above in chapter 8, the book states use "node server" to start the server.

The source code readme , however, states "you need to run the server using babel-cli: 'node_modules/.bin/babel-cli server.js'"

Neither of them work and both return the following error: "let markup = ReactDom.renderToString(<Router.RouterContext {...renderProps} />);

SyntaxError: Unexpected token < "

node_modules/authsrv-plugin-logout mentioned in chapter 07 example 05_plugin_module_impersonation does not exist

call spider function with nesting large than 1 would't work as expected

only two page had been download. and the callback never been call

i run cmd with your code:

$ node spider.js http://frps.eflora.cn/frps/Rosales

then a err comes--the file content i write to is undefined{1} .

function dowload(){
//...
 writeFile(filename, body))//{1}
//...
}

i think it may be good to change sth in :

• add another _agruments to save the aguments for function promisified({1})
• use the var at ({2},{3}) ,not agruments
  since here a function too, it may have its own arguments ({0})

-or change (not testing) args.push(function(err, result) { ...} to args.push((err, result)=>{...}

function promisify (callbackBasedApi) {
  return function promisified() {
    const args = [].slice.call(arguments);
    const _arguments = arguments; //{1}
    return new Promise((resolve, reject) => {  
      args.push(function(err, result) {     //{0}
        if(err) {
          return reject(err);       
        }
        if(_arguments.length <= 1) {       //{2}
          resolve(result);
        } else {
          resolve([].slice.call(_arguments, 1)); //{3}
        }
      });
      callbackBasedApi.apply(null, args);    
    });
  }
};

it may lead to the result of request operation in download function:

function dowload(){
//...
return request(url)
    .then(response => {
      body = response.body;
      //console.log(JSON.stringify(response));
     //the response is an array with length 2 . But it expect to an object since `request(url)`
    })
//...
}

thanky you !