NodeJS断点有时不起作用

Question

We are building a NodeJS 5.5.0 app using the --harmony command line flag to enable ES6. It is a very simple API proxying app so there is no data layer or front-end apart from the API responses themselves. The app is tied together with connect, using Swagger for the API itself. I am using IntelliJ 15 and everything is working well apart from debugging failing to consistently hit my breakpoints. I am finding this quite frustrating and a waste of dev time - perhaps I am missing something here as am new to the Node environment?

Here is my specific example:

app.js:

// requires here

swaggerTools.initializeMiddleware(swaggerDoc, function (middleware) {

// Interpret Swagger resources and attach metadata to request
app.use(middleware.swaggerMetadata());

// Validate Swagger requests
app.use(middleware.swaggerValidator());

// Route validated requests to appropriate controller
app.use(middleware.swaggerRouter(options));

// Serve the Swagger documents and Swagger UI
app.use(middleware.swaggerUi());

// Start the server
http.createServer(app).listen(serverPort, function () {
  console.log('Server is listening on port %d', serverPort);
    });
});
module.exports = app;

And then somewhere along the line we are using a transformer with object-mapper that runs on every API call:

transformer.js:

'use strict';
(function () {

    var util = require('util');

    //==> breakpoint #1 on the line below, successfully hit when the app launches
    module.exports = function (req, res, data, next) {

        console.log('GOT HERE!');

        //==> breakpoint #2 on the line below never hit but app hangs here
        var operation = req.swagger.operation;

        // more code here
    };
}).call(this);

Breakpoint #1 always works when the app launches, I skip it and make a call and 'GOT HERE!' is printed in the console as I would expect. The app hangs here indefinitely but I can't inspect any variables and the IDE doesn't register that it has hit the breakpoint. We've tested this outside of the IDE with node-inspector , Chrome tools and the native interactive node debugger but the same issue is present. I have also tested this on multiple versions of Node 4 and 5.

We've had to wrap most of our files with a function wrapper for the time being as we're using blanket for code coverage and it doesn't work without this. I have tried removing the function wrapper in transformer.js above but the debugger still doesn't hit breakpoint #2.

Can anyone please offer some insight on this as I'm out of ideas?

Answer 1

I have found the cause of this. It seems there is a potential bug with the Node debugger when it hits any line with util.inspect() on it it will hang there.

I have confirmed this is an issue in the latest versions of Node 4.2.6 and 5.5.0 as well as nightly builds 5.5.1 and 6.0.0.

See https://github.com/nodejs/node/issues/4906