ui/app/components/send/send-content/send-amount-row/amount-max-button/amount-max-button.utils.js


1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29

const {
  multiplyCurrencies,
  subtractCurrencies,
} = require('../../../../../conversion-util')
const ethUtil = require('ethereumjs-util')

function calcMaxAmount ({ balance, gasTotal, selectedToken, tokenBalance }) {
  const { decimals } = selectedToken || {}
  const multiplier = Math.pow(10, Number(decimals || 0))

  return selectedToken
    ? multiplyCurrencies(
      tokenBalance,
      multiplier,
      {
        toNumericBase: 'hex',
        multiplicandBase: 16,
      }
    )
    : subtractCurrencies(
      ethUtil.addHexPrefix(balance),
      ethUtil.addHexPrefix(gasTotal),
      { toNumericBase: 'hex' }
    )
}

module.exports = {
  calcMaxAmount,
}