formatObj.ts

function formatObj(obj: object) {
  const lines: [number, string][] = [];
  function fmt(obj: any, depth: number) {
    if (Array.isArray(obj)) {
      if (!obj.length) {
        lines.push([depth, 'none']);
      }
      for (const x of obj) {
        fmt(x, depth);
      }
    } else if (typeof obj === 'object') {
      for (const [k, v] of Object.entries(obj)) {
        if (Array.isArray(v)) {
          if (v.length) {
            lines.push([depth, `${k}:`]);
            fmt(v, depth + 1);
          } else {
            lines.push([depth, `${k}: none`]);
          }
        } else if (typeof v !== 'object') {
          lines.push([depth, `${k}: ${v}`]);
        } else {
          lines.push([depth, `${k}:`]);
          fmt(v, depth + 1);
        }
      }
    } else {
      lines.push([depth, obj.toString()]);
    }
  }
  fmt(obj, 0);
  return lines
    .map(([depth, line]) => '  '.repeat(depth) + '- ' + line)
    .join('\n');
}