viem/utils/signature/signatureToHex.ts

TypeScript Interface for Ethereum

import { secp256k1 } from '@noble/curves/secp256k1'

import type { ErrorType } from '../../errors/utils.js'
import type { Hex, Signature } from '../../types/misc.js'
import {
  type HexToBigIntErrorType,
  hexToBigInt,
} from '../../utils/encoding/fromHex.js'
import { type ToHexErrorType, toHex } from '../../utils/encoding/toHex.js'

export type SignatureToHexErrorType =
  | HexToBigIntErrorType
  | ToHexErrorType
  | ErrorType

/**
 * @description Converts a signature into hex format.
 *
 * @param signature The signature to convert.
 * @returns The signature in hex format.
 *
 * @example
 * signatureToHex({
 *   r: '0x6e100a352ec6ad1b70802290e18aeed190704973570f3b8ed42cb9808e2ea6bf',
 *   s: '0x4a90a229a244495b41890987806fcbd2d5d23fc0dbe5f5256c2613c039d76db8',
 *   v: 28n
 * })
 * // "0x6e100a352ec6ad1b70802290e18aeed190704973570f3b8ed42cb9808e2ea6bf4a90a229a244495b41890987806fcbd2d5d23fc0dbe5f5256c2613c039d76db81c"
 */
export function signatureToHex({ r, s, v }: Signature): Hex {
  return `0x${new secp256k1.Signature(
    hexToBigInt(r),
    hexToBigInt(s),
  ).toCompactHex()}${toHex(v).slice(2)}`
}