@tetcoin/util/compact/stripLength.js

A collection of useful utilities for @tetcoin

"use strict";

var _interopRequireDefault = require("@babel/runtime/helpers/interopRequireDefault");

Object.defineProperty(exports, "__esModule", {
  value: true
});
exports.default = compactStripLength;

var _slicedToArray2 = _interopRequireDefault(require("@babel/runtime/helpers/slicedToArray"));

var _defaults = require("./defaults");

var _fromU8a = _interopRequireDefault(require("./fromU8a"));

// Copyright 2017-2019 @polkadot/util authors & contributors
// This software may be modified and distributed under the terms
// of the Apache-2.0 license. See the LICENSE file for details.

/**
 * @name compactStripLength
 * @description Removes the length prefix, returning both the total length (including the value + compact encoding) and the decoded value with the correct length
 * @example
 * <BR>
 *
 * ```javascript
 * import { compactStripLength } from '@tetcoin/util';
 *
 * console.log(compactStripLength(new Uint8Array([2 << 2, 0xde, 0xad]))); // [2, Uint8Array[0xde, 0xad]]
 * ```
 */
function compactStripLength(input) {
  let bitLength = arguments.length > 1 && arguments[1] !== undefined ? arguments[1] : _defaults.DEFAULT_BITLENGTH;

  const _compactFromU8a = (0, _fromU8a.default)(input, bitLength),
        _compactFromU8a2 = (0, _slicedToArray2.default)(_compactFromU8a, 2),
        offset = _compactFromU8a2[0],
        length = _compactFromU8a2[1];

  const total = offset + length.toNumber();
  return [total, input.subarray(offset, total)];
}