/** One output column: the row key to read and, optionally, the header text to print instead of the key. */
export interface CsvColumn<Row> {
    /** Property of each row whose value fills this column. */
    key: keyof Row & string;
    /**
     * Header cell text.
     *
     * @default the key itself
     */
    label?: string | undefined;
}
/** Output options for {@link toCsv}; every field has a working default. */
export interface CsvOptions<Row> {
    /**
     * Columns to emit, in order; omit to emit every key of the first row.
     *
     * @default Object.keys(rows[0])
     */
    columns?: readonly (CsvColumn<Row> | (keyof Row & string))[] | undefined;
    /**
     * Field separator.
     *
     * @default ','
     */
    delimiter?: string | undefined;
    /**
     * Whether the first line is the header row.
     *
     * @default true
     */
    header?: boolean | undefined;
}
/**
 * Serialises rows to RFC 4180 CSV text — CRLF line ends, fields quoted only when
 * they contain the delimiter, a quote or a line break — ready for a Blob or a
 * data: URL. Dates print as ISO 8601; null and undefined print as empty fields.
 *
 * @example
 * ```ts
 * toCsv(rows, { columns: [{ key: 'name', label: 'Name' }, 'amount'] });
 * ```
 */
export declare function toCsv<Row extends object>(rows: readonly Row[], options?: CsvOptions<Row>): string;