Pretty printing XML with javascript
JavascriptXmlXsltPretty PrintJavascript Problem Overview
I have a string that represents a non indented XML that I would like to pretty-print. For example:
<root><node/></root>
should become:
<root>
<node/>
</root>
Syntax highlighting is not a requirement. To tackle the problem I first transform the XML to add carriage returns and white spaces and then use a pre tag to output the XML. To add new lines and white spaces I wrote the following function:
function formatXml(xml) {
var formatted = '';
var reg = /(>)(<)(\/*)/g;
xml = xml.replace(reg, '$1\r\n$2$3');
var pad = 0;
jQuery.each(xml.split('\r\n'), function(index, node) {
var indent = 0;
if (node.match( /.+<\/\w[^>]*>$/ )) {
indent = 0;
} else if (node.match( /^<\/\w/ )) {
if (pad != 0) {
pad -= 1;
}
} else if (node.match( /^<\w[^>]*[^\/]>.*$/ )) {
indent = 1;
} else {
indent = 0;
}
var padding = '';
for (var i = 0; i < pad; i++) {
padding += ' ';
}
formatted += padding + node + '\r\n';
pad += indent;
});
return formatted;
}
I then call the function like this:
jQuery('pre.formatted-xml').text(formatXml('<root><node1/></root>'));
This works perfectly fine for me but while I was writing the previous function I thought that there must be a better way. So my question is do you know of any better way given an XML string to pretty-print it in an html page? Any javascript frameworks and/or plugins that could do the job are welcome. My only requirement is this to be done on the client side.
Javascript Solutions
Solution 1 - Javascript
From the text of the question I get the impression that a string result is expected, as opposed to an HTML-formatted result.
If this is so, the simplest way to achieve this is to process the XML document with the identity transformation and with an <xsl:output indent="yes"/>
instruction:
<xsl:stylesheet version="1.0"
xmlns:xsl="http://www.w3.org/1999/XSL/Transform">
<xsl:output omit-xml-declaration="yes" indent="yes"/>
<xsl:template match="node()|@*">
<xsl:copy>
<xsl:apply-templates select="node()|@*"/>
</xsl:copy>
</xsl:template>
</xsl:stylesheet>
When applying this transformation on the provided XML document:
<root><node/></root>
most XSLT processors (.NET XslCompiledTransform, Saxon 6.5.4 and Saxon 9.0.0.2, AltovaXML) produce the wanted result:
<root> <node /> </root>
Solution 2 - Javascript
This can be done using native javascript tools, without 3rd party libs, extending the @Dimitre Novatchev's answer:
var prettifyXml = function(sourceXml)
{
var xmlDoc = new DOMParser().parseFromString(sourceXml, 'application/xml');
var xsltDoc = new DOMParser().parseFromString([
// describes how we want to modify the XML - indent everything
'<xsl:stylesheet xmlns:xsl="http://www.w3.org/1999/XSL/Transform">',
' <xsl:strip-space elements="*"/>',
' <xsl:template match="para[content-style][not(text())]">', // change to just text() to strip space in text nodes
' <xsl:value-of select="normalize-space(.)"/>',
' </xsl:template>',
' <xsl:template match="node()|@*">',
' <xsl:copy><xsl:apply-templates select="node()|@*"/></xsl:copy>',
' </xsl:template>',
' <xsl:output indent="yes"/>',
'</xsl:stylesheet>',
].join('\n'), 'application/xml');
var xsltProcessor = new XSLTProcessor();
xsltProcessor.importStylesheet(xsltDoc);
var resultDoc = xsltProcessor.transformToDocument(xmlDoc);
var resultXml = new XMLSerializer().serializeToString(resultDoc);
return resultXml;
};
console.log(prettifyXml('<root><node/></root>'));
Outputs:
<root>
<node/>
</root>
Note, as pointed out by @jat255, pretty printing with <xsl:output indent="yes"/>
is not supported by firefox. It only seems to work in chrome, opera and probably the rest webkit-based browsers.
Solution 3 - Javascript
Found this thread when I had a similar requirement but I simplified OP's code as follows:
function formatXml(xml, tab) { // tab = optional indent value, default is tab (\t)
var formatted = '', indent= '';
tab = tab || '\t';
xml.split(/>\s*</).forEach(function(node) {
if (node.match( /^\/\w/ )) indent = indent.substring(tab.length); // decrease indent by one 'tab'
formatted += indent + '<' + node + '>\r\n';
if (node.match( /^<?\w[^>]*[^\/]$/ )) indent += tab; // increase indent
});
return formatted.substring(1, formatted.length-3);
}
works for me!
Solution 4 - Javascript
Slight modification of efnx clckclcks's javascript function. I changed the formatting from spaces to tab, but most importantly I allowed
var formatXml = this.formatXml = function (xml) {
var reg = /(>)\s*(<)(\/*)/g; // updated Mar 30, 2015
var wsexp = / *(.*) +\n/g;
var contexp = /(<.+>)(.+\n)/g;
xml = xml.replace(reg, '$1\n$2$3').replace(wsexp, '$1\n').replace(contexp, '$1\n$2');
var pad = 0;
var formatted = '';
var lines = xml.split('\n');
var indent = 0;
var lastType = 'other';
// 4 types of tags - single, closing, opening, other (text, doctype, comment) - 4*4 = 16 transitions
var transitions = {
'single->single': 0,
'single->closing': -1,
'single->opening': 0,
'single->other': 0,
'closing->single': 0,
'closing->closing': -1,
'closing->opening': 0,
'closing->other': 0,
'opening->single': 1,
'opening->closing': 0,
'opening->opening': 1,
'opening->other': 1,
'other->single': 0,
'other->closing': -1,
'other->opening': 0,
'other->other': 0
};
for (var i = 0; i < lines.length; i++) {
var ln = lines[i];
// Luca Viggiani 2017-07-03: handle optional <?xml ... ?> declaration
if (ln.match(/\s*<\?xml/)) {
formatted += ln + "\n";
continue;
}
// ---
var single = Boolean(ln.match(/<.+\/>/)); // is this line a single tag? ex. <br />
var closing = Boolean(ln.match(/<\/.+>/)); // is this a closing tag? ex. </a>
var opening = Boolean(ln.match(/<[^!].*>/)); // is this even a tag (that's not <!something>)
var type = single ? 'single' : closing ? 'closing' : opening ? 'opening' : 'other';
var fromTo = lastType + '->' + type;
lastType = type;
var padding = '';
indent += transitions[fromTo];
for (var j = 0; j < indent; j++) {
padding += '\t';
}
if (fromTo == 'opening->closing')
formatted = formatted.substr(0, formatted.length - 1) + ln + '\n'; // substr removes line break (\n) from prev loop
else
formatted += padding + ln + '\n';
}
return formatted;
};
Solution 5 - Javascript
Personnaly, I use google-code-prettify with this function :
prettyPrintOne('<root><node1><root>', 'xml')
Solution 6 - Javascript
Or if you'd just like another js function to do it, I've modified Darin's (a lot):
var formatXml = this.formatXml = function (xml) {
var reg = /(>)(<)(\/*)/g;
var wsexp = / *(.*) +\n/g;
var contexp = /(<.+>)(.+\n)/g;
xml = xml.replace(reg, '$1\n$2$3').replace(wsexp, '$1\n').replace(contexp, '$1\n$2');
var pad = 0;
var formatted = '';
var lines = xml.split('\n');
var indent = 0;
var lastType = 'other';
// 4 types of tags - single, closing, opening, other (text, doctype, comment) - 4*4 = 16 transitions
var transitions = {
'single->single' : 0,
'single->closing' : -1,
'single->opening' : 0,
'single->other' : 0,
'closing->single' : 0,
'closing->closing' : -1,
'closing->opening' : 0,
'closing->other' : 0,
'opening->single' : 1,
'opening->closing' : 0,
'opening->opening' : 1,
'opening->other' : 1,
'other->single' : 0,
'other->closing' : -1,
'other->opening' : 0,
'other->other' : 0
};
for (var i=0; i < lines.length; i++) {
var ln = lines[i];
var single = Boolean(ln.match(/<.+\/>/)); // is this line a single tag? ex. <br />
var closing = Boolean(ln.match(/<\/.+>/)); // is this a closing tag? ex. </a>
var opening = Boolean(ln.match(/<[^!].*>/)); // is this even a tag (that's not <!something>)
var type = single ? 'single' : closing ? 'closing' : opening ? 'opening' : 'other';
var fromTo = lastType + '->' + type;
lastType = type;
var padding = '';
indent += transitions[fromTo];
for (var j = 0; j < indent; j++) {
padding += ' ';
}
formatted += padding + ln + '\n';
}
return formatted;
};
Solution 7 - Javascript
All of the javascript functions given here won't work for an xml document having unspecified white spaces between the end tag '>' and the start tag '<'. To fix them, you just need to replace the first line in the functions
var reg = /(>)(<)(\/*)/g;
by
var reg = /(>)\s*(<)(\/*)/g;
Solution 8 - Javascript
what about creating a stub node (document.createElement('div') - or using your library equivalent), filling it with the xml string (via innerHTML) and calling simple recursive function for the root element/or the stub element in case you don't have a root. The function would call itself for all the child nodes.
You could then syntax-highlight along the way, be certain the markup is well-formed (done automatically by browser when appending via innerHTML) etc. It wouldn't be that much code and probably fast enough.
Solution 9 - Javascript
If you are looking for a JavaScript solution just take the code from the Pretty Diff tool at http://prettydiff.com/?m=beautify
You can also send files to the tool using the s parameter, such as: http://prettydiff.com/?m=beautify&s=https://stackoverflow.com/
Solution 10 - Javascript
You can get pretty formatted xml with xml-beautify
var prettyXmlText = new XmlBeautify().beautify(xmlText,
{indent: " ",useSelfClosingElement: true});
indent:indent pattern like white spaces
useSelfClosingElement: true=>use self-closing element when empty element.
Original(Before)
<?xml version="1.0" encoding="utf-8"?><example version="2.0">
<head><title>Original aTitle</title></head>
<body info="none" ></body>
</example>
Beautified(After)
<?xml version="1.0" encoding="utf-8"?>
<example version="2.0">
<head>
<title>Original aTitle</title>
</head>
<body info="none" />
</example>
Solution 11 - Javascript
For a current project I had the need to prettify and colorize XML without extra libraries. The following self contained code works quite well.
function formatXml(xml,colorize,indent) {
function esc(s){return s.replace(/[-\/&<> ]/g,function(c){ // Escape special chars
return c==' '?' ':'&#'+c.charCodeAt(0)+';';});}
var sm='<div class="xmt">',se='<div class="xel">',sd='<div class="xdt">',
sa='<div class="xat">',tb='<div class="xtb">',tc='<div class="xtc">',
ind=indent||' ',sz='</div>',tz='</div>',re='',is='',ib,ob,at,i;
if (!colorize) sm=se=sd=sa=sz='';
xml.match(/(?<=<).*(?=>)|$/s)[0].split(/>\s*</).forEach(function(nd){
ob=('<'+nd+'>').match(/^(<[!?\/]?)(.*?)([?\/]?>)$/s); // Split outer brackets
ib=ob[2].match(/^(.*?)>(.*)<\/(.*)$/s)||['',ob[2],'']; // Split inner brackets
at=ib[1].match(/^--.*--$|=|('|").*?\1|[^\t\n\f \/>"'=]+/g)||['']; // Split attributes
if (ob[1]=='</') is=is.substring(ind.length); // Decrease indent
re+=tb+tc+esc(is)+tz+tc+sm+esc(ob[1])+sz+se+esc(at[0])+sz;
for (i=1;i<at.length;i++) re+=(at[i]=="="?sm+"="+sz+sd+esc(at[++i]):sa+' '+at[i])+sz;
re+=ib[2]?sm+esc('>')+sz+sd+esc(ib[2])+sz+sm+esc('</')+sz+se+ib[3]+sz:'';
re+=sm+esc(ob[3])+sz+tz+tz;
if (ob[1]+ob[3]+ib[2]=='<>') is+=ind; // Increase indent
});
return re;
}
Solution 12 - Javascript
Or just print out the special HTML characters?
Ex: <xmlstuff> 	<node /> </xmlstuff>
	 Horizontal tab
Line feed
Solution 13 - Javascript
XMLSpectrum formats XML, supports attribute indentation and also does syntax-highlighting for XML and any embedded XPath expressions:
XMLSpectrum is an open source project, coded in XSLT 2.0 - so you can run this server-side with a processor such as Saxon-HE (recommended) or client-side using Saxon-CE.
XMLSpectrum is not yet optimised to run in the browser - hence the recommendation to run this server-side.
Solution 14 - Javascript
here is another function to format xml
function formatXml(xml){
var out = "";
var tab = " ";
var indent = 0;
var inClosingTag=false;
var dent=function(no){
out += "\n";
for(var i=0; i < no; i++)
out+=tab;
}
for (var i=0; i < xml.length; i++) {
var c = xml.charAt(i);
if(c=='<'){
// handle </
if(xml.charAt(i+1) == '/'){
inClosingTag = true;
dent(--indent);
}
out+=c;
}else if(c=='>'){
out+=c;
// handle />
if(xml.charAt(i-1) == '/'){
out+="\n";
//dent(--indent)
}else{
if(!inClosingTag)
dent(++indent);
else{
out+="\n";
inClosingTag=false;
}
}
}else{
out+=c;
}
}
return out;
}
Solution 15 - Javascript
var formatXml = this.formatXml = function (xml) {
var reg = /(>)(<)(\/*)/g;
var wsexp = / *(.*) +\n/g;
var contexp = /(<.+>)(.+\n)/g;
xml = xml.replace(reg, '$1\n$2$3').replace(wsexp, '$1\n').replace(contexp, '$1\n$2');
var pad = 0;
var formatted = '';
var lines = xml.split('\n');
var indent = 0;
var lastType = 'other';
Solution 16 - Javascript
Xml formatting can be done by parsing the xml, adding or changing text nodes in the dom tree for indentation and then serializing the DOM back to xml.
Please check formatxml function in https://jsonbrowser.sourceforge.io/formatxml.js You can see the function in action in https://jsonbrowser.sourceforge.io/ under the Xml tab.
Below is the simplified code. formatxml.js adds error checking, optional removal of comments, indent as a parameter and handles non-space text between parent nodes.
const parser = new DOMParser();
const serializer = new XMLSerializer();
function formatXml(xml) {
let xmlDoc = parser.parseFromString(xml, 'application/xml');
let rootElement = xmlDoc.documentElement;
indentChildren(xmlDoc, rootElement, "\n", "\n ");
xml = serializer.serializeToString(xmlDoc);
return xml;
}
function indentChildren(xmlDoc, node, prevPrefix, prefix) {
let children = node.childNodes;
let i;
let prevChild = null;
let prevChildType = 1;
let child = null;
let childType;
for (i = 0; i < children.length; i++) {
child = children[i];
childType = child.nodeType;
if (childType != 3) {
if (prevChildType == 3) {
// Update prev text node with correct indent
prevChild.nodeValue = prefix;
} else {
// Create and insert text node with correct indent
let textNode = xmlDoc.createTextNode(prefix);
node.insertBefore(textNode, child);
i++;
}
if (childType == 1) {
let isLeaf = child.childNodes.length == 0 || child.childNodes.length == 1 && child.childNodes[0].nodeType != 1;
if (!isLeaf) {
indentChildren(xmlDoc, child, prefix, prefix + " ");
}
}
}
prevChild = child;
prevChildType =childType;
}
if (child != null) {
// Previous level indentation after last child
if (childType == 3) {
child.nodeValue = prevPrefix;
} else {
let textNode = xmlDoc.createTextNode(prevPrefix);
node.append(textNode);
}
}
}
Reference: https://www.w3schools.com/XML/dom_intro.asp
Solution 17 - Javascript
var reg = /(>)\s*(<)(\/*)/g;
xml = xml.replace(/\r|\n/g, ''); //deleting already existing whitespaces
xml = xml.replace(reg, '$1\r\n$2$3');
Solution 18 - Javascript
Use above method for pretty print and then add this in any div by using jquery text() method. for example id of div is xmldiv
then use :
$("#xmldiv").text(formatXml(youXmlString));
Solution 19 - Javascript
You could also use Saxon-JS client-side:
<script src="SaxonJS/SaxonJS2.js"></script>
<script>
let myXML = `<root><node/></root>`;
SaxonJS.getResource({
text: myXML.replace(`xml:space="preserve"`, ''),
type: "xml"
}).then(doc => {
const output = SaxonJS.serialize(doc, {method: "xml", indent: true, "omit-xml-declaration":true});
console.log(output);
})
</script>
Solution 20 - Javascript
This may involve creating nodes as objects, but you can have total control over exporting pretty formatted xml.
The following will return a string array of the lines which you can join with a new line delimiter "\n".
/**
* The child of an XML node can be raw text or another xml node.
*/
export type PossibleNode = XmlNode | string;
/**
* Base XML Node type.
*/
export interface XmlNode {
tag: string;
attrs?: { [key: string]: string };
children?: PossibleNode[];
}
/**
* Exports the given XML node to a string array.
*
* @param node XML Node
* @param autoClose Auto close the tag
* @param indent Indentation level
* @returns String array
*/
export function xmlNodeToString(
node: XmlNode,
autoClose: boolean = true,
indent: number = 0
): string[] {
const indentStr = " ".repeat(indent);
const sb: string[] = [];
sb.push(`${indentStr}<${node.tag}`);
if (node.attrs) {
for (const key in node.attrs) {
sb.push(`${indentStr} ${key}="${node.attrs[key]}"`);
}
}
if (node.children) {
if (node.children.length === 1 && typeof node.children[0] === "string") {
sb[sb.length - 1] += ">" + node.children[0];
} else {
sb.push(`${indentStr}>`);
for (const child of node.children) {
if (typeof child === "string") {
sb.push(`${indentStr} ${child}`);
} else {
const lines = xmlNodeToString(child, autoClose, indent + 1);
sb.push(...lines.map((line) => `${indentStr} ${line}`));
}
}
}
if (autoClose) {
if (node.children.length === 1 && typeof node.children[0] === "string") {
sb[sb.length - 1] += `</${node.tag}>`;
} else {
sb.push(`${indentStr}</${node.tag}>`);
}
}
} else {
if (autoClose) {
sb.push(`${indentStr}/>`);
} else {
sb.push(`${indentStr}>`);
}
}
return sb;
}
Updates appreciated on the gist: https://gist.github.com/rodydavis/acd609560ab0416b60681fddabc43eee
Solution 21 - Javascript
Xml-to-json library has method formatXml(xml).
I am the maintainer of the project.
var prettyXml = formatXml("<a><b/></a>");
// <a>
// <b/>
// </a>
Solution 22 - Javascript
This my version, maybe usefull for others, using String builder Saw that someone had the same piece of code.
public String FormatXml(String xml, String tab)
{
var sb = new StringBuilder();
int indent = 0;
// find all elements
foreach (string node in Regex.Split(xml,@">\s*<"))
{
// if at end, lower indent
if (Regex.IsMatch(node, @"^\/\w")) indent--;
sb.AppendLine(String.Format("{0}<{1}>", string.Concat(Enumerable.Repeat(tab, indent).ToArray()), node));
// if at start, increase indent
if (Regex.IsMatch(node, @"^<?\w[^>]*[^\/]$")) indent++;
}
// correct first < and last > from the output
String result = sb.ToString().Substring(1);
return result.Remove(result.Length - Environment.NewLine.Length-1);
}