Tips for debugging Node.js application in VSCode

Methods for efficiently debugging Node.js applications in VSCode include: 1. Configure the launch.json file, the example configuration is {"version": "0.2.0", "configurations": [{"type": "node", "request": "launch", "name": "Launch Program", "program": "${workspaceFolder}/app.js"}]}; 2. Start debugging, select configuration and play by clicking the debug icon; 3. Set breakpoints and click the code line number; 4. Use the debug toolbar to control execution, such as continuing, step by step, entering and jumping; 5. Use the conditional breakpoint, right-click the breakpoint to select Edit Breakpoint sets conditions; 6. Use the Watch window to monitor expressions; 7. Check the call stack to understand the execution process.

Debugging Node.js applications in VSCode is a must-have skill for developers. So, how to efficiently debug Node.js applications in VSCode? Let's take a deeper look.

When I was developing a Node.js application, debugging functionality was almost indispensable. The debugging tools provided by VSCode are not only powerful, but also very intuitive to use. Let's start with the basics and gradually deepen into some advanced techniques.

The first thing to do is to configure a debug startup file, which is usually done through the launch.json file. Here is a simple configuration example:

 {
    "version": "0.2.0",
    "configurations": [
        {
            "type": "node",
            "request": "launch",
            "name": "Launch Program",
            "program": "${workspaceFolder}/app.js"
        }
    ]
}

This configuration tells VSCode how to start your Node.js application. program field specifies the script file to be started, in this example app.js

After configuration, debugging becomes very simple. You can start debugging by clicking the debug icon on the left side of VSCode, selecting Launch Program you just configured, and then clicking the play button. At this time, VSCode will start your Node.js application and display the currently executed line of code in the debug panel on the left.

One of the most commonly used functions during debugging is to set breakpoints. You can set a breakpoint by clicking on the line number to the left of the line of code. When the code is executed to a breakpoint, the program pauses, giving you the opportunity to check the value of the variable, step through the code, or skip certain code segments.

After setting a breakpoint, you can use the buttons in the debug toolbar to control the execution of the program. Click the继续button to keep the program running until the next breakpoint.单步跳过can skip the execution of the current function.单步进入will enter the inside of the current function.单步跳出will execute the current function and return to the position where it was called.

In addition to basic debugging functions, VSCode also provides many advanced features. For example, you can use conditional breakpoints to pause program execution only when a specific condition is met. This is very useful for debugging complex logic. The way to set a conditional breakpoint is to right-click on the breakpoint and select Edit Breakpoint and enter your condition, such as i > 10 .

Another advanced trick is to use the Watch window. You can add expressions in Watch window, and VSCode will calculate and display the values ​​of these expressions in real time during debugging. This is useful for monitoring the values ​​of specific variables or complex expressions.

During debugging, viewing the call stack is also a very useful feature. There is a Call Stack window in the debug panel of VSCode, which displays the currently executed function call chain. You can click on any line in the stack and jump to the corresponding line of code, which is very helpful for understanding the execution process of the code.

Of course, some common problems may be encountered during debugging. For example, if your program is not pausing at the expected location, it may be because you are not properly configuring the launch.json file, or you are not properly setting the breakpoint. Another common problem is that the program fails to start, which may be due to permission issues or the dependency package is not installed correctly.

When it comes to performance optimization, using debugging tools can help you find bottlenecks in your code. VSCode's debugging tool can display the execution time of each function, helping you identify which parts need to be optimized.

Overall, debugging Node.js applications in VSCode is a very useful skill. By mastering these techniques, you can develop and maintain your Node.js applications more efficiently. Remember, debugging is not only about finding errors, but also an important means to deeply understand the code execution process.

The above is the detailed content of Tips for debugging Node.js application in VSCode. For more information, please follow other related articles on the PHP Chinese website!