type Stringify<T> = {
    [key in keyof T]: string;
};
type Textify<T> = {
    [key in keyof T]: string | number;
};
export declare function exists(filePath: string): Promise<boolean>;
export declare function mkdir(path: string): Promise<void>;
export declare function rmFile(path: string): Promise<void>;
export interface IStorage<P> {
    read(): Promise<P | null>;
    write(item: P): Promise<void>;
}
export interface IListStorage<P> {
    append(row: P | P[]): Promise<void>;
}
export declare abstract class BaseFileStorage<P> implements IStorage<P> {
    folderPath: string;
    fileName: string;
    protected constructor(folderPath: string, fileName: string);
    delete(): Promise<void>;
    exists(filePath?: string): Promise<boolean>;
    protected createFolder(): Promise<void>;
    protected get filePath(): string;
    abstract read(): Promise<P | null>;
    abstract write(item: P): Promise<void>;
}
export declare abstract class BaseListFileStorage<P> extends BaseFileStorage<P[]> implements IListStorage<P> {
    abstract append(row: P | P[]): Promise<void>;
}
export declare class JsonStorage<P extends object> extends BaseFileStorage<P> {
    folderPath: string;
    fileName: string;
    constructor(folderPath: string, fileName: string);
    write(data: P): Promise<void>;
    read(): Promise<P | null>;
}
export declare class CsvStorage<P extends object> extends BaseListFileStorage<P> {
    readonly folderPath: string;
    readonly fileName: string;
    protected readonly onRead: (row: Stringify<P>) => P;
    protected readonly onWrite: (row: P) => Textify<P>;
    constructor(folderPath: string, fileName: string, onRead: (row: Stringify<P>) => P, onWrite: (row: P) => Textify<P>);
    read(): Promise<P[] | null>;
    write(rows: P[]): Promise<void>;
    append(row: P | P[]): Promise<void>;
}
export declare class InMemoryStorage<P extends object> implements IStorage<P> {
    private value;
    read(): Promise<P | null>;
    write(item: P): Promise<void>;
}
export declare class InMemoryListStorage<P extends object> implements IListStorage<P> {
    private list;
    read(): Promise<P[] | null>;
    write(item: P[]): Promise<void>;
    append(row: P[] | P): Promise<void>;
}
export {};
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