Now in your terminal or command prompt you will find the breakpoint is hit.Īll debugging commands together Execution controlls:.Debug with the command: "node debug Index.js".Open your terminal or command prompt and navigate to your project folder.Here I've set a debugger in "/test" route callback. Response.write("We are in test route \n") Server.get("/", function (request, response) ) Configure our HTTP server to respond with Hello World the root request Load the node-router library by creationix Load the http module to create an http server. Lets take the example of the app below, which is similar to our first node application: Here the breakpoints inside the route callback will not be hit when you start debugging rather it will be when you hit the required url. This is exactly similar as the points mentioned above. To view the values of the watch expressions, use the following commands:Įven after every command of step forward, watchers will be automatically printed. adding variable b and c in the watch expressionĪt any point of time you can add any expression in the watch array or remove one. Below is the example of adding an expression in watcher, removing it, and getting the values of all the expressions added in watchers. You can press ctrl+c to come out of repl.Īs you can set watch expressions in Node also as you do it in Chrome. Once you are in debugger's repl, you can type any variable name and hit enter to get the value. To open debugger's repl for evaluation in debugging script's context, you can use the following command: Repl: check expression values, execute script Still it provides some simple ways to retrieve info from the variables or the running program.
Node debugger is not as smart as that in Chrome. The functionality of the pause button in Chrome developer's tool can be achieved by the following command in Node:Ĭhecking the values, watch expressions, executing scripts The command "o" can perform the same thing for you. Same thing is done in Node by executing the following command: To go out of the step mentioned in the previous point you use "Shift + F11" in Chrome. The command "s" can perform the same thing for you. To go inside a function or doing similar thing you use "F11" in Chrome. The "n" command can also do the same for you. Similar thing is done by the following command in Node: In case of Chrome you use "F10" to go to the next stem. The "c" command can also do the same for you.
In Node you do it with the following command: In Chrome developer's tool you can continue execution of the program, or go to one breakpoint to next by pressing "F8" key. Here we are describing the stepping commands comparing with that the developer's tools of Google Chrome. The function is taking the first argument as file name, cause if your app may require some other files. clearBreakpoint() does exactly the opposite
In this way you can set a breakpoint while running the app, without doing any modification in the code. Now write "debugger " at any part of the program and it will be the breakpoint. Before running the app, you open the MyAppFile.js file in a text editor. This is similar to setting a breakpoint in Visual Studio, or any other IDE like that. There are two ways to put a breakpoint in a program. Use ctrl+c two times simultaneously to come out of the debug panel. This command will simply start running the app from the beginning.Īt any given point of time you can restart the app. To run the app again, you simply can use the following command: This command will stop running the app but will not bring you out from the debugging panel. To stop or kill the app you debugging, the command is: To run the application in debugging mode the command is:Įxecuting the command mentioned above, will lead you to the debugging panel as well as it will start the debugging for "MyAppFile.js". Generally you run a program with the command: "node MyAppFile.js". Start/Stop debugging: run, kill or restart app Start debugging Here is the program which we are gonna debug
Today we are going to see how we can use this debugger to debug a node program. Node has a built-in client which uses this debugger. This debugger is accessible out of process via a TCP-Protocol. Node uses V8 Runtime JavaScript engine, which comes with an extensive debugger. If you can't debug, you wont be able to develop big applications. Debugging is as important as development.
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