import { TransformerBase } from '../base';
import { Params } from '../base/estimator';
import { CSRMatrix, NumericMatrix } from '../data';
export interface TfidfTransformerProps {
    norm?: 'l1' | 'l2' | null;
    useIdf?: boolean;
    smoothIdf?: boolean;
    sublinearTf?: boolean;
}
export declare class TfidfTransformer extends TransformerBase<NumericMatrix, CSRMatrix> {
    readonly acceptedInputKinds: readonly ["dense", "csr"];
    private norm;
    private useIdf;
    private smoothIdf;
    private sublinearTf;
    private idfState;
    constructor(props?: TfidfTransformerProps);
    getParams(): Params;
    private validateCounts;
    fit(X: NumericMatrix): void;
    transform(X: NumericMatrix): CSRMatrix;
    get idf(): number[];
}