Light weight CSV paser function that works in old versions of JavaScript

parseCSV.js

/**
 * parseCSV
 * Light weight CSV paser function that works in old versions of JavaScript
 * @version 1.0.0
 * @author McShaman
 * @licence MIT
 */

(function(window) {
	
	'use strict';
	
	/**
	 * The main parser function
	 * @param {string} dat - CSV data
	 * @param {Object} ops - Options
	 * @param {boolean} [ops.headerRow=false] - Items in first row are column headings
	 * @param {boolean} [ops.strict=false] - Rows must have the same number of columns 
	 */
	window.parseCSV = function(dat, ops){
		
		var fields = [],
			rows = [],
			headerRow = false,
			options = {
				headerRow: false,
				strict: false
			};
		
		for(var property in ops) {
			
			if(options.hasOwnProperty(property)) {
				
				options[property] = ops[property];
				
			}
			
		}
		
		var	matches,
			match,
			pattern = /(?!$)([^\",\r\n]+|\"([^\"]*(\"{2}[^\"]*)*)\"|^)*(,|\r?\n|\r)?/g;
		
		while((matches = pattern.exec(dat))){
			
			if(matches[2]){ // Quote wrapped match found
				
				if(matches[3]) { // Double quoting match found
					
					match = replaceDoubleQuoting(matches[2]);
					
				} else {
					
					match = matches[2];
					
				}
				
			} else { // Unwrapped match found
				
				match = matches[1];
				
			}
			
			fields.push(match);
			
			if(!matches[4] || matches[4] !== ',') {
				rows.push(fields);
				fields = [];
			}
			
		}
		
		if(options.strict) {
			if(!rowLengthsEqual(rows)) {
				return false;
			}
		}
		
		if(options.headerRow) {
			rows = useFirstRowAsHeaders(rows);
		}
		
		return rows;
		
	};
	
	var replaceDoubleQuoting = function(str) {
		
		var pattern = /\"\"/g;
		
		return str.replace(pattern, '"');
		
	};
	
	var rowLengthsEqual = function(arys) {
		
		var equal = arys[0].length;
		
		for(var i = 0, leng = arys.length; i < leng; i++) {
			
			if(arys[i].length !== equal) {
				return false;
			}
			
		}
		
		return true;
		
	};
	
	var useFirstRowAsHeaders = function(ary) {
		
		var rows = ary.slice(1),
			row,
			rowsIndex,
			rowsLength,
			headers = ary[0],
			header, 
			headersIndex, 
			headersLength,
			object,
			newArray = [];
		
		for(rowsIndex = 0, rowsLength = rows.length; rowsIndex < rowsLength; rowsIndex++) {
			
			object = {};
			
			row = rows[rowsIndex];
			
			for(headersIndex = 0, headersLength = headers.length; headersIndex < headersLength; headersIndex++) {
				
				header = headers[headersIndex];
				
				object[header] = row[headersIndex];
				
			}
			
			newArray.push(object);
			
		}
		
		return newArray;
		
	};
	
})(this);