redux-devtools/packages/redux-devtools-inspector-monitor/src/tabs/getJsonTreeTheme.ts

import { Base16Theme } from 'redux-devtools-themes';
import { StylingConfig } from 'react-base16-styling';

export default function getJsonTreeTheme(
  base16Theme: Base16Theme
): StylingConfig {
  return {
    extend: base16Theme,
    nestedNode: ({ style }, keyPath, nodeType, expanded) => ({
      style: {
        ...style,
        whiteSpace: expanded ? 'inherit' : 'nowrap',
      },
    }),
    nestedNodeItemString: ({ style }, keyPath, nodeType, expanded) => ({
      style: {
        ...style,
        display: expanded ? 'none' : 'inline',
      },
    }),
  };
}