How to debug a Gulp task?

Question

How do I debug a gulp task defined in my gulpfile.js with a debugger such as the Google Chrome debugger, stepping through the task's code line by line?

Answer 1

With Node.js version 6.3+ you can use the --inspect flag when running your task.

To debug a gulp task named css:

1. Find out where your gulp executable lives. If gulp is installed locally, this will be at node_modules/.bin/gulp. If gulp is installed globally, run which gulp (Linux/Mac) or where gulp (Windows) in a terminal to find it.

2. Run one of these commands according to your version of Node.js. If required, replace ./node_modules/.bin/gulp with the path to your gulp installation from step 1.

   • Node.js 6.3+: node --inspect --debug-brk ./node_modules/.bin/gulp css
   • Node.js 7+: node --inspect-brk ./node_modules/.bin/gulp css

3. Use Chrome to browse to chrome://inspect.

The --debug-brk (Node.js 6.3+) and --inspect-brk (Node.js 7+) flags are used to pause code execution on the first line of code of your task. This gives you a chance to open up the Chrome debugger and set breakpoints before the task finishes.

If you don't want the debugger to pause on first line of code, just use the --inspect flag.

You can also install the Node.js Inspector Manager (NIM) extension for Chrome to help with step 3. This will automatically open up a Chrome tab with the debugger ready to go, as an alternative to manually browsing to a URL.