zap-desktop/app/lib/utils/crypto.js

import bitcoin from 'bitcoinjs-lib'
import bech32 from 'lib/utils/bech32'

/**
 * Turns parsed number into a string.
 */
export const formatValue = (integer, fractional) => {
  let value
  if (fractional && fractional.length > 0) {
    value = `${integer}.${fractional}`
  } else {
    // Empty string means `XYZ.` instead of just plain `XYZ`.
    if (fractional === '') {
      value = `${integer}.`
    } else {
      value = `${integer}`
    }
  }
  return value
}

/**
 * Splits number into integer and fraction.
 */
export const parseNumber = (_value, precision) => {
  let value = String(_value || '')
  if (typeof _value === 'string') {
    value = _value.replace(/[^0-9.]/g, '')
  }
  let integer = null
  let fractional = null
  if (value * 1.0 < 0) {
    value = '0.0'
  }
  // pearse integer and fractional value so that we can reproduce the same string value afterwards
  // [0, 0] === 0.0
  // [0, ''] === 0.
  // [0, null] === 0
  if (value.match(/^[0-9]*\.[0-9]*$/)) {
    ;[integer, fractional] = value.toString().split(/\./)
    if (!fractional) {
      fractional = ''
    }
  } else {
    integer = value
  }
  // Limit fractional precision to the correct number of decimal places.
  if (fractional && fractional.length > precision) {
    fractional = fractional.substring(0, precision)
  }

  return [integer, fractional]
}

/**
 * Test to see if a string is a valid on-chain address.
 * @param {String} input string to check.
 * @param {String} [network='mainnet'] network to check (mainnet, testnet).
 * @return {Boolean} boolean indicating wether the address is a valid on-chain address.
 */
export const isOnchain = (input, chain = 'bitcoin', network = 'mainnet') => {
  if (chain !== 'bitcoin') {
    // TODO: Implement address checking for litecoin.
    return true
  }
  try {
    bitcoin.address.toOutputScript(
      input,
      network === 'mainnet' ? bitcoin.networks.bitcoin : bitcoin.networks.testnet
    )
    return true
  } catch (e) {
    return false
  }
}

/**
 * Test to see if a string is a valid lightning address.
 * @param {String} input string to check.
 * @param {String} [network='bitcoin'] chain to check (bitcoin, litecoin).
 * @param {String} [network='mainnet'] network to check (mainnet, testnet, regtest).
 * @return {Boolean} boolean indicating wether the address is a lightning address.
 */
export const isLn = (input, chain = 'bitcoin', network = 'mainnet') => {
  let prefix = 'ln'
  // Prefixes come from SLIP-0173
  // See https://github.com/satoshilabs/slips/blob/master/slip-0173.md
  if (chain === 'bitcoin') {
    switch (network) {
      case 'mainnet':
        prefix = 'lnbc'
        break
      case 'testnet':
        prefix = 'lntb'
        break
      case 'regtest':
        prefix = 'lnbcrt'
        break
    }
  } else if (chain === 'litecoin') {
    switch (network) {
      case 'mainnet':
        prefix = 'lnltc'
        break
      case 'testnet':
        prefix = 'lntltc'
        break
      case 'regtest':
        prefix = 'lnrltc'
        break
    }
  }

  if (!input.startsWith(prefix)) {
    return false
  }

  try {
    bech32.decode(input)
    return true
  } catch (e) {
    return false
  }
}