269 Debugging Tools 406df18f

Debugging Tools

Debuggers by Language

Node.js / TypeScript

# Start with inspector
node --inspect dist/main.js

# Break on first line
node --inspect-brk dist/main.js

# With ts-node
node --inspect -r ts-node/register src/main.ts

// In code
debugger; // Breakpoint

// Quick print
console.log({ variable }); // Shows name and value
console.table(arrayOfObjects); // Table format
console.trace('Called from'); // Stack trace

Python

# Start debugger
python -m pdb script.py

# Post-mortem on exception
python -m pdb -c continue script.py

# In code
breakpoint()  # Python 3.7+
import pdb; pdb.set_trace()  # Older Python

# Quick print
print(f"{variable=}")  # Python 3.8+ shows name and value

# Rich debugging
from rich import inspect
inspect(object, methods=True)

pdb Commands

Go

# Start delve
dlv debug ./cmd/app

# Attach to running process
dlv attach <pid>

# Debug test
dlv test ./pkg/...

// Quick print
log.Printf("%+v", variable) // With field names
fmt.Printf("%#v\n", variable) // Go syntax representation

// Spew for complex structures
import "github.com/davecgh/go-spew/spew"
spew.Dump(variable)

Delve Commands

VS Code Debug Config

// .vscode/launch.json
{
  "version": "0.2.0",
  "configurations": [
    {
      "type": "node",
      "request": "launch",
      "name": "Debug TypeScript",
      "program": "${workspaceFolder}/src/main.ts",
      "preLaunchTask": "tsc: build",
      "outFiles": ["${workspaceFolder}/dist/**/*.js"]
    },
    {
      "type": "python",
      "request": "launch",
      "name": "Debug Python",
      "program": "${workspaceFolder}/main.py",
      "console": "integratedTerminal"
    }
  ]
}

Quick Reference