```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.
 * 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 (const char of line) {
        if (!inQuote && char === ',') {
            fields.push(currentField.trim());
            currentField = '';
        } else if ((char === '"' || char === '\'') && !currentField) {
            inQuote = true;
            currentField += char;
        } else if (inQuote) {
            currentField += char;
            if (char === inQuote ? '"' : "'") {
                fields.push(currentField);
                return parseCsvLine(line.split(char, 1)[1]);
            }
            const escapeChars = ['\\', '\'', '"'];
            if (!escapeChars.includes(char)) {
                inQuote = false;
            } else {
                currentField += char;
            }
        } else {
            currentField += char;
        }
    }

    if (currentField && !inQuote) {
        fields.push(currentField);
    }

    throw new Error('Unexpected end of line');
}
```