viem/utils/data/trim.ts

TypeScript Interface for Ethereum

import type { ErrorType } from '../../errors/utils.js'
import type { ByteArray, Hex } from '../../types/misc.js'

type TrimOptions = {
  dir?: 'left' | 'right' | undefined
}
export type TrimReturnType<value extends ByteArray | Hex> = value extends Hex
  ? Hex
  : ByteArray

export type TrimErrorType = ErrorType

export function trim<value extends ByteArray | Hex>(
  hexOrBytes: value,
  { dir = 'left' }: TrimOptions = {},
): TrimReturnType<value> {
  let data: any =
    typeof hexOrBytes === 'string' ? hexOrBytes.replace('0x', '') : hexOrBytes

  let sliceLength = 0
  for (let i = 0; i < data.length - 1; i++) {
    if (data[dir === 'left' ? i : data.length - i - 1].toString() === '0')
      sliceLength++
    else break
  }
  data =
    dir === 'left'
      ? data.slice(sliceLength)
      : data.slice(0, data.length - sliceLength)

  if (typeof hexOrBytes === 'string') {
    if (data.length === 1 && dir === 'right') data = `${data}0`
    return `0x${
      data.length % 2 === 1 ? `0${data}` : data
    }` as TrimReturnType<value>
  }
  return data as TrimReturnType<value>
}