@parity/api/src/util/wei.ts

The Parity Promise-based API library for interfacing with Ethereum over RPC

// Copyright 2015-2019 Parity Technologies (UK) Ltd.
// This file is part of Parity.
//
// SPDX-License-Identifier: MIT

import BigNumber from 'bignumber.js';

import { EtherDenomination } from '../types';

const UNITS: EtherDenomination[] = [
  'wei',
  'ada',
  'babbage',
  'shannon',
  'szabo',
  'finney',
  'ether',
  'kether',
  'mether',
  'gether',
  'tether'
];

/**
 * Returns the multiplication factor from wei to another ether denomination.
 *
 * @param unit - An ether denomiation.
 * @example
 * _getUnitMultiplier('wei'); // 1
 * _getUnitMultiplier('ether'); // 10^^18
 * @ignore
 */
export const _getUnitMultiplier = (unit: EtherDenomination) => {
  const position = UNITS.indexOf(unit.toLowerCase() as EtherDenomination);

  if (position === -1) {
    throw new Error(`Unknown unit ${unit} passed to wei formatter`);
  }

  return Math.pow(10, position * 3);
};

/**
 * Convert from wei to another ether denomination.
 *
 * @param value - The value in wei.
 * @param unit - The ether denomination to convert to.
 */
export const fromWei = (
  value: string | number | BigNumber,
  unit: EtherDenomination = 'ether'
) => new BigNumber(value).dividedBy(_getUnitMultiplier(unit));

/**
 * Convert a value from an ether denomination to wei.
 *
 * @param value - The value in the ether denomination.
 * @param unit - The ether denomination to convert to.
 */
export const toWei = (
  value: string | number | BigNumber,
  unit: EtherDenomination = 'ether'
) => new BigNumber(value).multipliedBy(_getUnitMultiplier(unit));