I want to create an xml attribute but in order to find the element I want to add the query on, I need to use xpath. How can I do this?
Example =
const xmlText = `<?xml version="1.0" encoding="ISO-8859-1"?>
<bookstore>
<book>
<title lang="eng">Harry Potter</title>
<price>29.99</price>
</book>
<book>
<title id="somethingeng">Learning XML</title>
<price>39.95</price>
</book>
</bookstore>`;
var doc = new DOMParser().parseFromString(xmlText,'text/xml');
var r = doc.evaluate("//*[@lang[contains(.,'eng')]]", doc, null, XPathResult.ANY_TYPE, null);
I want to create an attribute for this r;
First of all the xmlText string should be a template literals now that is has new lines.
evaluate() seamed fine, but the result of that is a XPathResult that needs to be iterated with XPathResult.iterateNext().
const xmlText = `<?xml version="1.0" encoding="ISO-8859-1"?>
<bookstore>
<book>
<title lang="eng">Harry Potter</title>
<price>29.99</price>
</book>
<book>
<title id="somethingeng">Learning XML</title>
<price>39.95</price>
</book>
</bookstore>`;
var doc = new DOMParser().parseFromString(xmlText,'text/xml');
var r = doc.evaluate("//*[@lang[contains(.,'eng')]]", doc, null, XPathResult.ANY_TYPE, null);
var next = r.iterateNext();
while (next) {
console.log(next.textContent);
next = r.iterateNext();
}Based on the iterator you need to collect the nodes that you are interested in and then alter them afterwards. In the following I created functions that can create child elements and attributes based on a XPath expression and an object representing the new data.
const xmlText = `<?xml version="1.0" encoding="ISO-8859-1"?>
<bookstore>
<book>
<title lang="eng">Harry Potter</title>
<price>29.99</price>
</book>
<book>
<title id="somethingeng">Learning XML</title>
<price>39.95</price>
</book>
</bookstore>`;
var doc = new DOMParser().parseFromString(xmlText, 'text/xml');
function addAttribute(doc, xpath, obj) {
let r = doc.evaluate(xpath, doc, null, XPathResult.ANY_TYPE, null);
let nodes = [];
let next = r.iterateNext();
while (next) {
nodes.push(next);
next = r.iterateNext();
}
nodes.forEach(node => {
Object.keys(obj).forEach(key => {
let newattr = doc.createAttribute(key);
newattr.value = obj[key];
node.setAttributeNode(newattr);
});
});
}
function addChildNode(doc, xpath, obj) {
let r = doc.evaluate(xpath, doc, null, XPathResult.ANY_TYPE, null);
let nodes = [];
let next = r.iterateNext();
while (next) {
console.log(next.textContent);
nodes.push(next);
next = r.iterateNext();
}
nodes.forEach(node => {
Object.keys(obj).forEach(key => {
let newnode = doc.createElement(key);
newnode.textContent = obj[key];
node.appendChild(newnode);
});
});
}
addAttribute(doc, "//title[@lang[contains(.,'eng')]]", {"data-lang":"eng", index: 2});
addChildNode(doc, "//book[number(price) < 30]", {sale: true});
console.log(doc.documentElement.outerHTML);Found the solution by using XPathResult.snapshotItem().
var xmlText = `<?xml version="1.0" encoding="ISO-8859-1"?>
<bookstore>
<book>
<title lang="eng">Harry Potter</title>
<price>29.99</price>
</book>
<book>
<title id=\"somethingeng\">Learning XML</title>
<price>39.95</price>
</book>
</bookstore>`;
var doc = new DOMParser().parseFromString(xmlText, 'text/xml');
var r = doc.evaluate("//*[@id[contains(.,'eng')]]", doc, null, XPathResult.ORDERED_NODE_SNAPSHOT_TYPE, null);
var index = 0;
while (index < r.snapshotLength) {
var next = r.snapshotItem(index);
next.setAttribute("value", "val");
index++;
}
var xmlSerializer = new XMLSerializer();
const updatedDoc = xmlSerializer.serializeToString(doc);
console.log(updatedDoc);