/**
 * Converts an array of integers made up of 'from' bits into an
 * array of integers made up of 'to' bits. The output array is
 * zero-padded if necessary, unless strict mode is true.
 * Throws a {@link ValidationError} if input is invalid.
 * Original by Pieter Wuille: https://github.com/sipa/bech32.
 *
 * @param {Uint8Array} data Array of integers made up of 'from' bits.
 * @param {number} from Length in bits of elements in the input array.
 * @param {number} to Length in bits of elements in the output array.
 * @param {bool} strictMode Require the conversion to be completed without padding.
 * @returns {Uint8Array}
 */
export declare function convertBits(data: Uint8Array, from: number, to: number, strictMode?: boolean): Uint8Array;