@tetcoin/util/hex/hasPrefix.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 = hexHasPrefix;

var _hex = _interopRequireDefault(require("../is/hex"));

// 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 hexHasPrefix
 * @summary Tests for the existence of a `0x` prefix.
 * @description
 * Checks for a valid hex input value and if the start matched `0x`
 * @example
 * <BR>
 *
 * ```javascript
 * import { hexHasPrefix } from '@tetcoin/util';
 *
 * console.log('has prefix', hexHasPrefix('0x1234')); // => true
 * ```
 */
function hexHasPrefix(value) {
  return !!(value && (0, _hex.default)(value, -1, true) && value.substr(0, 2) === '0x');
}