@polkadot/util/u8a/toBn.js

A collection of useful utilities for @polkadot

// Copyright 2017-2022 @polkadot/util authors & contributors
// SPDX-License-Identifier: Apache-2.0
import { BN } from "../bn/bn.js";
import { isBoolean } from "../is/boolean.js";
import { objectSpread } from "../object/spread.js";
/**
 * @name u8aToBn
 * @summary Creates a BN from a Uint8Array object.
 * @description
 * `UInt8Array` input values return the actual BN. `null` or `undefined` values returns an `0x0` value.
 * @param value The value to convert
 * @param options Options to pass while converting
 * @param options.isLe Convert using Little Endian (default)
 * @param options.isNegative Convert using two's complement
 * @example
 * <BR>
 *
 * ```javascript
 * import { u8aToBn } from '@polkadot/util';
 *
 * u8aToHex(new Uint8Array([0x68, 0x65, 0x6c, 0x6c, 0xf])); // 0x68656c0f
 * ```
 */

/** @deprecated Use hexToBn (value?: string | null, options?: ToBnOptions) */
function u8aToBn(value, options = {}) {
  // NOTE: This is the same process as followed in the hexToBn conversion
  // For Uint8Array, default to LE
  const {
    isLe,
    isNegative
  } = objectSpread({
    isLe: true,
    isNegative: false
  }, isBoolean(options) ? {
    isLe: options
  } : options);
  const bn = new BN(value, isLe ? 'le' : 'be');
  return isNegative && value.length ? bn.fromTwos(value.length * 8) : bn;
}

export { u8aToBn };