Signature Utilities

---

parseSignature

function parseSignature(sig: string): CsMastSignature | null

Parses a CS-MAST-S PHC string into its constituent parts.

Returns null for any invalid input (see validation rules below).

Parameters

Parameter	Type	Description
sig	string	A CS-MAST-S PHC string to parse

Returns

CsMastSignature on success, null on failure.

Validation Rules

Returns null when:

• Input does not start with $
• Structure is not exactly $v=N$params$hashHex
• v is not a positive integer
• hash, lang, or prsr are missing from params
• Both scat and sinc are absent
• hashHex is not exactly 64 lowercase hex characters

Example

import { parseSignature } from '@shriyanss/cs-mast';

const parsed = parseSignature(
  '$v=1$hash=sha256,lang=js,lver=es6,prsr=-babel/parser,scat=lit_val$' + 'a'.repeat(64)
);

// {
//   version: 1,
//   hash: 'sha256',
//   lang: 'js',
//   lver: 'es6',
//   prsr: '-babel/parser',
//   scat: ['lit', 'val'],
//   sinc: [],
//   hashHex: 'aaa...'
// }

console.log(parseSignature('invalid')); // null
console.log(parseSignature(''));        // null

---

buildSignature

function buildSignature(parts: CsMastSignature): string

Assembles a CS-MAST-S PHC string from its parts. Does not perform any hashing — accepts a pre-computed hashHex.

Parameters

Parameter	Type	Description
parts	CsMastSignature	All fields of the signature

Returns

A valid CS-MAST-S PHC string.

Example

import { buildSignature } from '@shriyanss/cs-mast';

const sig = buildSignature({
  version: 1,
  hash: 'sha256',
  lang: 'js',
  lver: 'es6',
  prsr: '-babel/parser',
  scat: ['lit', 'val'],
  sinc: ['ReturnStatement'],
  hashHex: 'a3f2b1' + 'c'.repeat(58),
});

// $v=1$hash=sha256,lang=js,lver=es6,prsr=-babel/parser,scat=lit_val,sinc=ReturnStatement$a3f2b1cccc...

Round-trip

buildSignature(parseSignature(sig)!) is lossless for any valid signature.

---

buildSignatureFromConfig

function buildSignatureFromConfig(config: CsMastConfig, hashHex: string): string

Convenience wrapper that builds a signature from a CsMastConfig and a pre-computed hash, automatically sanitizing the prsr field.

Parameters

Parameter	Type	Description
config	CsMastConfig	Configuration object
hashHex	string	64-char lowercase SHA-256 hex

Example

import { buildSignatureFromConfig } from '@shriyanss/cs-mast';

const sig = buildSignatureFromConfig(
  { hash: 'sha256', lang: 'js', prsr: '@babel/parser', scat: ['lit'], sinc: [] },
  'a3f2b1' + '0'.repeat(58),
);
// prsr is automatically sanitized: '@babel/parser' → '-babel/parser'

---

sanitizePrsr

function sanitizePrsr(name: string): string

Applies the CS-MAST-S character-set rule to a parser name: characters outside [a-zA-Z0-9/+.-] are replaced with -.

Example

import { sanitizePrsr } from '@shriyanss/cs-mast';

sanitizePrsr('@babel/parser')    // '-babel/parser'
sanitizePrsr('tree-sitter/py')   // 'tree-sitter/py'
sanitizePrsr('my parser v2')     // 'my-parser-v2'