json-parser-yaml-converter/src/lexer.js

Enhanced JSON Parser with verbose error messages and JSON to YAML conversion

/**
 * This module exports the main lexer.
 *
 * @module lexer
 */


'use strict';

import { nearleyLexer } from '@juanrguezsu7/lexer-generator';

const SPACE = /(?<SPACE>\s+)/; SPACE.skip = true;
const LK = /(?<LK>\{)/;
const RK = /(?<RK>\})/;
const COLON = /(?<COLON>:)/;
const LB = /(?<LB>\[)/;
const RB = /(?<RB>\])/;
const NULL = /(?<NULL>null)/; NULL.value = () => null;
const TRUE = /(?<TRUE>true)/; TRUE.value = () => true;
const FALSE = /(?<FALSE>false)/; FALSE.value = () => false;
const COMMA = /(?<COMMA>,)/;
const NUMBER = /(?<NUMBER>[-+]?\d+(?:\.\d+)?(?:[eE][-+]?\d+)?)/; NUMBER.value = x => Number(x);
const STRING = /(?<STRING>"(?:[^"\\]|\\.)*")/; STRING.value = x => x.slice(1, -1);

const TOKENS = [
  SPACE,
  LK,
  RK,
  COLON,
  LB,
  RB,
  NULL,
  TRUE,
  FALSE,
  COMMA,
  NUMBER,
  STRING
];

const ERROR = /(?<ERROR>(.)+)/;

const lexer = nearleyLexer(TOKENS, {}, ERROR);

export { lexer };