```typescript
/**
 * Splits one line of CSV into its fields on commas.
 *
 * A field wrapped in double quotes may contain commas, and a doubled quote inside such a field means one literal quote character;
 * the surrounding quotes are not part of the value. Fields that are not quoted are taken literally, including any surrounding spaces.
 * An empty line is one empty field.
 */
export function parseCsvLine(line: string): string[] {
  const result = [];
  let currentField = '';
  let inQuote = false;

  for (let i = 0; i < line.length; i++) {
    const char = line[i];

    if (char === '"') {
      inQuote = !inQuote;
      continue;
    }

    if (!inQuote && char === ',') {
      result.push(currentField.trim());
      currentField = '';
      continue;
    }

    currentField += char;
  }

  if (result.length > 0) {
    result[0] = currentField.trim();
  } else if (currentField !== '') {
    throw new Error('Empty line without quoted field');
  }

  return result;
}
```