How to Debug JavaScript in VS Code

· Category: VS Code & Developer Tools

Short answer

VS Code has a built-in debugger that works with Node.js and browsers. You set breakpoints, inspect variables, and step through code without leaving the editor.

Steps

  1. Open the Run and Debug view on the left sidebar.
  2. Click "create a launch.json file" and select Node.js or Chrome.
  3. Set breakpoints by clicking the gutter next to line numbers.
  4. Press F5 to start debugging and F10 to step over functions.
  5. Watch variables and the call stack in the Debug sidebar.

Tips

  • Use conditional breakpoints that only trigger when an expression is true.
  • The Debug Console lets you evaluate expressions while paused.
  • Source maps enable debugging of transpiled TypeScript or bundled code.

Common issues

  • The debugger may not attach if the port is already in use.
  • Ensure your launch configuration points to the correct program entry file.