Extract a detailed JSON parse error (with line and column) in nodejs

jsonError.js

'use strict';
var clarinet = require('clarinet');

/**
   * Extract a detailed JSON parse error 
   * using https://github.com/dscape/clarinet
   * 
   * @param {string} json
   * @returns {{snippet:string, message:string, line:number, column:number, position:number}} or undefined if no error
   */
function getJSONParseError(json) {
    var parser = clarinet.parser(),
      firstError = undefined;

    // generate a detailed error using the parser's state
    function makeError(e) {
      var currentNL = 0, nextNL= json.indexOf('\n'), line = 1;
      while (line < parser.line) {
        currentNL = nextNL;
        nextNL = json.indexOf('\n', currentNL + 1);
        ++line;
      }
      return {
        snippet:json.substr(currentNL + 1, nextNL - currentNL - 1),
        message: (e.message || '').split('\n', 1)[0],
        line:parser.line,
        column:parser.column
      }
    }
    
    // trigger the parse error
    parser.onerror = function(e) {
      firstError = makeError(e);
      parser.close();
    };
    try {
      parser.write(json).close();
    } catch(e) {
      if (firstError === undefined) {
        return makeError(e);
      } else {
        return firstError;
      }
    }
    
    return firstError;
  }