Errors

CS-MAST exports three error classes, all extending Error.

---

ParseError

Thrown by cs_mast_init (via the adapter's parse() method) when the source code cannot be parsed — for example, due to a syntax error.

class ParseError extends Error {
  readonly source: string;     // the raw source string that failed
  readonly parserName: string; // e.g. '@babel/parser'
}

Example

import { cs_mast_init, ParseError } from '@shriyanss/cs-mast';

try {
  cs_mast_init('const = =;', config);
} catch (e) {
  if (e instanceof ParseError) {
    console.error('Parse failed:', e.message);
    console.error('Parser:', e.parserName);
  }
}

---

ConfigError

Thrown by cs_mast_init when the CsMastConfig is invalid.

class ConfigError extends Error {
  readonly field: string; // which field is invalid, e.g. 'hash', 'scat/sinc'
}

Causes

Condition	field
hash is missing or unsupported	'hash'
lang is missing	'lang'
prsr is missing	'prsr'
Both scat and sinc are empty	'scat/sinc'

Example

import { cs_mast_init, ConfigError } from '@shriyanss/cs-mast';

try {
  cs_mast_init('let x = 1;', {
    hash: 'sha256', lang: 'js', prsr: '@babel/parser',
    scat: [],  // ← empty
    sinc: [],  // ← empty
  });
} catch (e) {
  if (e instanceof ConfigError) {
    console.error(`Invalid config field: ${e.field}`);
    // → "Invalid config field: scat/sinc"
  }
}

---

MutationError

Thrown by the guardPath() proxy when a restricted mutation method is called on a CS-MAST tree path. See Mutation Guard.

class MutationError extends Error {
  readonly method: string; // name of the blocked method, e.g. 'remove'
}

Example

import { guardPath, MutationError } from '@shriyanss/cs-mast';

const safePath = guardPath(babelNodePath);

try {
  safePath.remove();
} catch (e) {
  if (e instanceof MutationError) {
    console.error(`Blocked: ${e.method}`);
    // → "Blocked: remove"
    console.error(e.message);
    // → "CS-MAST mutation guard: 'remove' is not allowed..."
  }
}