declare module 'merkle-tools' {
  export type Proof<T> = { left: T } | { right: T };

  class MerkleTree {
    constructor(options: { hashType: string });

    getMerkleRoot(): Buffer | null;
    getProof(index: number): Proof<string>[] | null;
    getProof(index: number, asBinary: false): Proof<string>[] | null;
    getProof(index: number, asBinary: true): Proof<Buffer>[] | null;
    getLeaf(index: number): Buffer | null;
    getLeafCount(): number;
    getTreeReadyState(): boolean;
    addLeaf(value: string | Buffer, doHash?: boolean): void;
    addLeaves(value: string[], doHash?: boolean): void;
    makeTree(doubleHash?: boolean): void;
    makeBTCTree(doubleHash?: boolean): void;
    validateProof(
      proof: Proof<string | Buffer>,
      targetHash: string | Buffer,
      merkleRoot: string | Buffer,
      doubleHash?: boolean,
    ): boolean;
  }

  export default MerkleTree;
}