VSCode Chrome Debugger custom variable

Question

I want to replace some text like ${relativeFile}.replace("docs/", "").

Remove docs/ and .md.

launch.json

{
  "version": "0.2.0",
  "configurations": [
    {
      "type": "pwa-chrome",
      "request": "launch",
      "name": "Launch Chrome against localhost",
      "url": "http://localhost:3000/${relativeFile}",
      "webRoot": "${workspaceFolder}/docs/"
    }
  ]
}

Launch with ${workspaceFolder}/docs/index.md

Got http://localhost:3000/docs/index.md

Expected http://localhost:3000/index