There is currently no API to access colors of current theme in VS Code Extensions, nor the meta information of them. It frustrated me for a long while, until today I came up with a dirty but working solution.

Since most of the themes follow the conversions of having Light or Dark in their names. Then we can have:

import { workspace } from 'vscode'

export function isDarkTheme() {
  const theme = workspace.getConfiguration()
    .get('workbench.colorTheme', '')

  // must be dark
  if (theme.match(/dark|black/i) != null)
    return true

  // must be light
  if (theme.match(/light/i) != null)
    return false

  // IDK, maybe dark
  return true
}

Simple, but surprisingly, it works really well. This is used for my Browse Lite extension to inject the preferred color schema matching with VS Code’s theme. And also Iconify IntelliSense for VS Code to update icons color with the theme.