Signature Operations

/**
 * Parse signature into complete Signature object with all components
 * @param signature - SignatureLike input (bytes, hex string, or object)
 * @returns Complete Signature object with r, s, v, recoveryParam, _vs, yParityAndS, compact
 * @throws Error if signature format is invalid
 */
function splitSignature(signature: SignatureLike): Signature;

import { splitSignature } from "@ethersproject/bytes";

// Parse 65-byte signature (standard format)
const sig65 = "0x1234567890abcdef1234567890abcdef1234567890abcdef1234567890abcdef1234567890abcdef1234567890abcdef1234567890abcdef1234567890abcdef1b";
const parsed1 = splitSignature(sig65);
// Result: {
//   r: "0x1234567890abcdef1234567890abcdef1234567890abcdef1234567890abcdef12",
//   s: "0x34567890abcdef1234567890abcdef1234567890abcdef1234567890abcdef12",
//   v: 27,
//   recoveryParam: 0,
//   _vs: "0x34567890abcdef1234567890abcdef1234567890abcdef1234567890abcdef12",
//   yParityAndS: "0x34567890abcdef1234567890abcdef1234567890abcdef1234567890abcdef12",
//   compact: "0x1234...full compact representation"
// }

// Parse 64-byte signature (EIP-2098 compact format)
const sig64 = "0x1234567890abcdef1234567890abcdef1234567890abcdef1234567890abcdef1234567890abcdef1234567890abcdef1234567890abcdef1234567890abcdef92";
const parsed2 = splitSignature(sig64);
// Automatically extracts v from high bit of s component

// Parse object format
const sigObj = {
  r: "0x1234567890abcdef1234567890abcdef1234567890abcdef1234567890abcdef12",
  s: "0x34567890abcdef1234567890abcdef1234567890abcdef1234567890abcdef12",
  v: 27
};
const parsed3 = splitSignature(sigObj);

// Parse with recoveryParam instead of v
const sigRecovery = {
  r: "0x1234567890abcdef1234567890abcdef1234567890abcdef1234567890abcdef12",
  s: "0x34567890abcdef1234567890abcdef1234567890abcdef1234567890abcdef12",
  recoveryParam: 0
};
const parsed4 = splitSignature(sigRecovery);

/**
 * Combine signature components into 65-byte signature format
 * @param signature - SignatureLike input with signature components
 * @returns Hex string containing 65-byte signature (r + s + v)
 */
function joinSignature(signature: SignatureLike): string;

import { joinSignature, splitSignature } from "@ethersproject/bytes";

// Join from object format
const sigComponents = {
  r: "0x1234567890abcdef1234567890abcdef1234567890abcdef1234567890abcdef12",
  s: "0x34567890abcdef1234567890abcdef1234567890abcdef1234567890abcdef12",
  v: 27
};
const joined1 = joinSignature(sigComponents);
// Result: "0x1234567890abcdef...1234567890abcdef121b" (65 bytes total)

// Join from already parsed signature
const signature = "0x1234567890abcdef1234567890abcdef1234567890abcdef1234567890abcdef1234567890abcdef1234567890abcdef1234567890abcdef1234567890abcdef1b";
const parsed = splitSignature(signature);
const rejoined = joinSignature(parsed);
// Result: Same as original signature

// Round-trip conversion
const original = {
  r: "0xabcdef1234567890abcdef1234567890abcdef1234567890abcdef1234567890ab",
  s: "0x1234567890abcdef1234567890abcdef1234567890abcdef1234567890abcdef12",
  recoveryParam: 1
};
const bytes = joinSignature(original);
const reparsed = splitSignature(bytes);
// reparsed will have all signature components properly calculated

type SignatureLike = {
  r: string;
  s?: string;
  _vs?: string;
  recoveryParam?: number;
  v?: number;
} | BytesLike;

interface Signature {
  /** R component of the signature (32 bytes) */
  r: string;
  /** S component of the signature (32 bytes) */
  s: string;
  /** Combined v and s value (EIP-2098 format) */
  _vs: string;
  /** Recovery parameter (0 or 1) */
  recoveryParam: number;
  /** V value (typically 27 or 28) */
  v: number;
  /** Alias for _vs (y parity and s combined) */
  yParityAndS: string;
  /** Compact signature format (r + _vs) */
  compact: string;
}