We have discussed a lot of topics at length. But how can we debug an created Node.js application.
For this, we have a number of methods available
1. Using Command Line tools
2. GUI
3. And few others
Using Command-Line tools
1. Console.log is the simplest debugging mechanism. You can insert it at different points in the code block and find the state of the program.
2. Node’s built-in debugger Node uses a debugging interface provided by the V8 virtual machine. In order to stop the application execution, we can use Node’s use built-in debugger.
3. Node Inspector provides GUI for debugging Node program.
By default, node run on daemon port or PORT 8080 and can be launched using the command
node-inspector
following which you use
node debug-brk
Let's understand this with an example:
Create a javascript file named
debugging-demo.js
On Running
Let's debug the application now
4. The pointer is currently at the anonymous function (highlighted)
Press n to move the pointer to run/debug the next statement
Which is
let index=0
(Highlighted in the undermentioned diagram)
Press n again to move the pointer to next executing statement
which is comparison operation inside the loop
Index<100 (highlighted)
Pressing n again
Pressing n again
Pressing n again (Highlighted)
applying comparison operator returning False
Pressing n
Applying increment operator
and so on.
Study Material