ether-unit-converter/webUtilsEth.js

The utility functions provide a conversation assortment of common utility functions, and can easily convert Wei to value and value to Wei without a round number.

const Web3 = require('web3');
const EthJsUnit = require('./ethJsUnit');

function getUnitValue(unit) {
  unit = unit ? unit : '';
  if (!EthJsUnit.unitMap[unit]) {
    throw new Error(
      'This unit "' +
        unit +
        '" doesn\'t exist, please use the one of the following units' +
        JSON.stringify(EthJsUnit.unitMap, null, 2),
    );
  }
  return unit;
};
var fromWei = (number, unit) => {
  unit = getUnitValue(unit);

  if (!Web3.utils.isBN(number) && !(typeof number === 'string')) {
    throw new Error(
      'Please pass numbers as strings or BN objects to avoid precision errors.',
    );
  }
  return Web3.utils.isBN(number)
    ? EthJsUnit.fromWei(number, unit)
    : EthJsUnit.fromWei(number, unit).toString(10);
};

var toWei = (number, unit) => {
  unit = getUnitValue(unit);

  if (!Web3.utils.isBN(number) && !(typeof number === 'string')) {
    throw new Error(
      'Please pass numbers as strings or BN objects to avoid precision errors.',
    );
  }

  return Web3.utils.isBN(number)
    ? EthJsUnit.toWei(number, unit)
    : EthJsUnit.toWei(number, unit).toString(10);
};

module.exports = {
  fromWei,
  toWei,
  getUnitValue,
};