launch.json 

{
    "version": "0.2.0",
    "configurations": [
      {
        "name": "Next.js: debug server-side",
        "type": "node-terminal",
        "request": "launch",
        "command": "npm run dev"
      },
      {
        "name": "Next.js: debug client-side",
        "type": "pwa-chrome",
        "request": "launch",
        "url": "http://localhost:3000"
      },
      {
        "name": "Next.js: debug full stack",
        "type": "node-terminal",
        "request": "launch",
        "command": "npm run dev",
        "console": "integratedTerminal",
        "serverReadyAction": {
          "pattern": "started server on .+, url: (https?://.+)",
          "uriFormat": "%s",
          "action": "debugWithChrome"
        }
      }
    ]
  }

参考Advanced Features: Debugging | Next.js