```ts
export function parseCsvLine(line: string): string[] {
  /**
   * 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.
   */
  const fields = [];
  let currentField = '';
  let inQuote = false;

  for (const char of line) {
    if (char === '"') {
      inQuote = !inQuote;
    } else if (!inQuote && char === ',') {
      if (currentField) {
        fields.push(currentField);
        currentField = '';
      }
    } else if (!inQuote) {
      currentField += char;
    }
  }

  if (currentField) {
    fields.push(currentField);
  }

  if (fields.some(field => field.startsWith('"') && !field.endsWith('"'))) {
    const unmatchedQuotes = fields.filter(field => field.startsWith('"') && !field.endsWith('"')).map(field => field[1]);
    throw new Error(`Unmatched quotes in line: ${unmatchedQuotes.join(', ')}`);
  }

  return fields;
}
```