Debugging in Node.js

To enter debugging mode in Node.js in the command line, use the inspect command like this:

node inspect app.js

Once inside debugging mode, you can write:

Navigation commands:

list() in which you pass the number of lines you want to see.

list(10)

n to execute the next line:

c to continue on until the program completes.

Once in debug mode, we can use repl to read, eval, print and loop. Inside repl mode, we can check the status of our variables.

We can also write debugger in our Node.js file to start the debugger at a specific place in our file.

Example:

var person = {
  name: "Charlie"
}

person.age = 28

debugger;

person.name = "George";

To start debugging your Node.js app in the Chrome dev tools, type the following command in the command line:

node --inspect-brk app.js

Then, open a new tab in Chrome, enter chrome://inspect and click on the link Open Dedicated DevTools for Node.js.