What Is Express?Įxpress is a minimal and flexible Node.js web application framework that provides a robust set of features for web and mobile applications. Node.js is an open-source, cross-platform JavaScript run-time environment and allows you to run JavaScript on the server. If one packages an application using Docker and the same works on his/her desktop, the same will work on any datacenter, any cloud provider and definitely on Alibaba Cloud's Simple Application Server. Docker helps provide "Universal portability / repeatability" and solves the biggest problem faced by developers who are starting up namely 'IT WORKS ON MY COMPUTER' phenomenon. You may be wondering why Docker when you can deploy my application directly as shown in the above article. This is a parallel article from my previous article Developing Node.js App in Visual Studio and Deploying on Simple Application Server.
#Node.js visual studio code tutorial code
In this article, we look at the steps one has to do to develop their node.js applications in visual studio code and deploy the same on Alibaba cloud. This article is meant for individual developers or startups with developers who are not very familiar with deployments and are currently using PaaS solutions for the same. Go back to the browser window and enjoy the updated experience.By Arnab Choudhuri, Alibaba Cloud Community Blog author Remove the breakpoint and detach the debugger by clicking the stop button. You can now step through the debugger once again and see that the lines cycle properly – no more undefined. However, your browser tab might have errored out – go refresh it if so.
nodemon detected the event and restarted the application.Upon saving the file, Docker detected the filesystem change event and proxied it through to the container.This is because several things have just happened:
A second or two later, you should see the debugger detach and then reattach (the yellow line highlighting the breakpoint will disappear and reappear). Replace the > with >= in the conditional on the next line: The reason becomes clear if you open up the “Closure” section under “VARIABLES”: lineIndex has incremented to 4 – the length of the LINES array – when it should have been reset after getting to 3. You can see it cycling through the lines, and then the bug shows up – right after the last line, message gets set to undefined. It’ll hit the breakpoint every time the browser refreshes, which is every 2 seconds. Hit the Play button at the top to resume code execution. If not, go back and refresh it – VSCode will pop back to the front as soon as the debugger hits it. If your browser window is still open and refreshing, in a second or two you should see it hit the breakpoint.
Set a breakpoint by clicking in the gutter, just to the left of the line number. Now go back to app.js and find the line that reads lineIndex += 1 line, just after we initialize the message variable. With the “Attach” config selected, click the “play” button to start the debugger. remoteRoot is set to the path of the code directory inside the container, because it’s almost certainly different than the path to the code on your machine.restart is set to true, so that the debugger re-attaches when the app restarts.The whole “Launch” config has been deleted – you’re using Compose to launch the app, not VSCode, so it’s unnecessary.Using your terminal, navigate to the directory with the app files and start up the app: Finally, it maps port 5858 inside the container to the same port on localhost, so you can connect to the remote debugger.It maps port 8000 inside the container to port 8000 on localhost, so you can actually visit the application.This is very useful, as it means you don’t have to rebuild the image every time you make a change to the application.
#Node.js visual studio code tutorial update
This means that the code inside the running container will update whenever you update the local files on your hard drive.
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