```ts
/**
 * 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.
 *
 * Throws an Error for a quoted field that is never closed.
 */
export function parseCsvLine(line: string): string[] {
    const fields = [];
    let currentField = '';
    let inQuote = false;

    for (let i = 0; i < line.length; i++) {
        if (line[i] === '"') {
            inQuote = !inQuote;
            currentField += line[i];
        } else if (!inQuote && line[i] === ',') {
            fields.push(currentField.trim());
            currentField = '';
        } else if (!inQuote) {
            currentField += line[i];
        }
    }

    if (currentField && inQuote) {
        throw new Error('Unbalanced quote in CSV line');
    }

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

    return fields;
}
```