plbowers/csvStringToArray.js

## csvStringToArray.js
const csvStringToArray = (strData, header=true) =>
{
    //const objPattern = new RegExp(("(\\,|\\r?\\n|\\r|^)(?:\"([^\"]*(?:\"\"[^\"]*)*)\"|([^\\,\\r\\n]*))"),"gi");
      const objPattern = new RegExp(("(\\,|\\r?\\n|\\r|^)(?:\"((?:\\\\.|\"\"|[^\\\\\"])*)\"|([^\\,\"\\r\\n]*))"),"gi");
    let arrMatches = null, arrData = [[]];
    while (arrMatches = objPattern.exec(strData)){
        if (arrMatches[1].length && arrMatches[1] !== ",") arrData.push([]);
        arrData[arrData.length - 1].push(arrMatches[2] ?
            arrMatches[2].replace(new RegExp( "[\\\\\"](.)", "g" ), '$1') :
            arrMatches[3]);
    }
    if (header) {
        hData = arrData.shift();
        hashData = arrData.map(row => {
            let i = 0;
            return hData.reduce(
                (acc, key) => {
                    acc[key] = row[i++];
                    return acc;
                },
                {}
            );
        });
        return hashData;
    } else {
        return arrData;
    }
}

## testbed
<html>
    <body>
        <input type="checkbox" name="hasHeader" id="hasHeader" value="1" checked="checked" />Has Header<br />
        <textarea id="foo" name="foo" cols="80" rows="10" />
h1,h2,h3,h4,h5
a,b,c,d,e
a,b,,d,
first,"second
with
multi-line",third,fourth,fifth
1,2,3,4,5,extra field that is ignored/lost if using headers
g,"h with ""embedded quotes"" asdf",i,j,k
l,"m with \"escaped quotes\" asdf",n,o,p
q,"r with \,escaped \,commas asdf",s,t,u
x,y,z</textarea>
        <button onclick="doIt()">doIt</button>
        <h3>Results</h3>
        <div id="results">
        </div>
    </body>
<script>
const csvStringToArray = (strData, header=true) =>
{
    //const objPattern = new RegExp(("(\\,|\\r?\\n|\\r|^)(?:\"([^\"]*(?:\"\"[^\"]*)*)\"|([^\\,\\r\\n]*))"),"gi");
      const objPattern = new RegExp(("(\\,|\\r?\\n|\\r|^)(?:\"((?:\\\\.|\"\"|[^\\\\\"])*)\"|([^\\,\"\\r\\n]*))"),"gi");
    let arrMatches = null, arrData = [[]];
    while (arrMatches = objPattern.exec(strData)){
        if (arrMatches[1].length && arrMatches[1] !== ",") arrData.push([]);
        arrData[arrData.length - 1].push(arrMatches[2] ?
            arrMatches[2].replace(new RegExp( "[\\\\\"](.)", "g" ), '$1') :
            arrMatches[3]);
    }
    if (header) {
        hData = arrData.shift();
        hashData = arrData.map(row => {
            let i = 0;
            return hData.reduce(
                (acc, key) => {
                    acc[key] = row[i++];
                    return acc;
                },
                {}
            );
        });
        return hashData;
    } else {
        return arrData;
    }
}
function doIt() {
    var h = document.getElementById('hasHeader');
    var v = document.getElementById('foo');
    var r = document.getElementById('results');
    //console.log(h, h.checked);
    var a = csvStringToArray(v.value, h.checked);
    r.innerHTML = JSON.stringify(a, function(k, v) { return v === undefined ? '<i>(undefined)</i>' : v; }).replace(/},{/g, '},<br />\n{');
    console.log(a);
}
</script>
</html>
	const csvStringToArray = (strData, header=true) =>
	{
	//const objPattern = new RegExp(("(\\,\|\\r?\\n\|\\r\|^)(?:\"([^\"](?:\"\"[^\"]))\"\|([^\\,\\r\\n]))"),"gi");
	const objPattern = new RegExp(("(\\,\|\\r?\\n\|\\r\|^)(?:\"((?:\\\\.\|\"\"\|[^\\\\\"]))\"\|([^\\,\"\\r\\n]))"),"gi");
	let arrMatches = null, arrData = [[]];
	while (arrMatches = objPattern.exec(strData)){
	if (arrMatches[1].length && arrMatches[1] !== ",") arrData.push([]);
	arrData[arrData.length - 1].push(arrMatches[2] ?
	arrMatches[2].replace(new RegExp( "[\\\\\"](.)", "g" ), '$1') :
	arrMatches[3]);
	}
	if (header) {
	hData = arrData.shift();
	hashData = arrData.map(row => {
	let i = 0;
	return hData.reduce(
	(acc, key) => {
	acc[key] = row[i++];
	return acc;
	},
	{}
	);
	});
	return hashData;
	} else {
	return arrData;
	}
	}
	<html>
	<body>
	<input type="checkbox" name="hasHeader" id="hasHeader" value="1" checked="checked" />Has Header<br />
	<textarea id="foo" name="foo" cols="80" rows="10" />
	h1,h2,h3,h4,h5
	a,b,c,d,e
	a,b,,d,
	first,"second
	with
	multi-line",third,fourth,fifth
	1,2,3,4,5,extra field that is ignored/lost if using headers
	g,"h with ""embedded quotes"" asdf",i,j,k
	l,"m with \"escaped quotes\" asdf",n,o,p
	q,"r with \,escaped \,commas asdf",s,t,u
	x,y,z</textarea>
	<button onclick="doIt()">doIt</button>
	<h3>Results</h3>
	<div id="results">
	</div>
	</body>
	<script>
	const csvStringToArray = (strData, header=true) =>
	{
	//const objPattern = new RegExp(("(\\,\|\\r?\\n\|\\r\|^)(?:\"([^\"](?:\"\"[^\"]))\"\|([^\\,\\r\\n]))"),"gi");
	const objPattern = new RegExp(("(\\,\|\\r?\\n\|\\r\|^)(?:\"((?:\\\\.\|\"\"\|[^\\\\\"]))\"\|([^\\,\"\\r\\n]))"),"gi");
	let arrMatches = null, arrData = [[]];
	while (arrMatches = objPattern.exec(strData)){
	if (arrMatches[1].length && arrMatches[1] !== ",") arrData.push([]);
	arrData[arrData.length - 1].push(arrMatches[2] ?
	arrMatches[2].replace(new RegExp( "[\\\\\"](.)", "g" ), '$1') :
	arrMatches[3]);
	}
	if (header) {
	hData = arrData.shift();
	hashData = arrData.map(row => {
	let i = 0;
	return hData.reduce(
	(acc, key) => {
	acc[key] = row[i++];
	return acc;
	},
	{}
	);
	});
	return hashData;
	} else {
	return arrData;
	}
	}
	function doIt() {
	var h = document.getElementById('hasHeader');
	var v = document.getElementById('foo');
	var r = document.getElementById('results');
	//console.log(h, h.checked);
	var a = csvStringToArray(v.value, h.checked);
	r.innerHTML = JSON.stringify(a, function(k, v) { return v === undefined ? '<i>(undefined)</i>' : v; }).replace(/},{/g, '},<br />\n{');
	console.log(a);
	}
	</script>
	</html>