src/utils.ts
import * as R from 'ramda'
/**
* This will take an Ethereum hex string (or a normal hex string) and
* output a normal hex string (no '0x' header) or throw an error on a
* bad hex string.
*
* @param {string} hex
*
* @returns {string}
* the hex string.
*/
export const cleanEthHex = (hex: string) => {
if (hex === '0x0') {
return '00'
}
// hex must be even - only exception above
if (hex.length % 2 !== 0) {
throw Error(`Bad hex string: ${hex}`)
}
// this covers the case hex=="0x" => ""
if (hex.slice(0, 2) === '0x') {
return hex.slice(2)
}
return hex
}
/**
* This compares ethereum addresses (taking into account case, etc)
*
* @param {string} addr1
* @param {string} addr2
*
* @returns {bool}
*/
export const ethAddrEq = (addr1: string, addr2: string) => {
const _clean = a => module.exports.cleanEthHex(a).toLowerCase()
// throw a length check in there to ensure we have valid addresses
return _clean(addr1) === _clean(addr2) && addr1.length === 42
}
// this is from the bech32 spec (Bitcoin)
const B32_ALPHA = 'qpzry9x8gf2tvdw0s3jn54khce6mua7l'
const toAlphabet = (arr: number[]) => {
var ret = ''
for (let i = 0; i < arr.length; i++) {
ret += B32_ALPHA.charAt(arr[i])
}
return ret
}
/**
* This will convert a hex string to Base32 in the bech32 format WITHOUT a checksum.
*
* @param {string} hex
* The hex string to convert to Base32 - can be an EthHex or plain hex string.
*
* @returns {string}
* The Base32 version of the hex string.
*/
export const hexToBase32 = (hex: string) => {
const _hex = cleanEthHex(hex)
const buf = Buffer.from(_hex, 'hex')
const digits = [0]
let digitlength = 1
let carry
for (let i = 0; i < buf.length; ++i) {
carry = buf[i]
for (let j = 0; j < digitlength; ++j) {
carry += digits[j] * 256
digits[j] = carry % 32
carry = (carry / 32) | 0
}
while (carry > 0) {
digits[digitlength] = carry % 32
digitlength++
carry = (carry / 32) | 0
}
}
return toAlphabet(R.reverse(digits.slice(0, digitlength)))
}