Generating XML attribute through XPath

Question

Generating XML attribute through XPath

How can I create an XML attribute using XPath to find the element I want to add the query on?

For 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 am looking to define an attribute for this 'r'.

javascript xml xpath

Answer 1

Answer №1

Initially, the xmlText string needs to be converted into a template literals format with new lines included.

evaluate() seemed adequate, but the outcome is an XPathResult requiring iteration using 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();
}

Modification

Considering the iterator, it's essential to gather the nodes of interest and then make modifications afterward. Below are functions created for generating child elements and attributes based on an 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);

Answer 2

Initially, the xmlText string needs to be converted into a template literals format with new lines included.

evaluate() seemed adequate, but the outcome is an XPathResult requiring iteration using 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();
}

Modification

Considering the iterator, it's essential to gather the nodes of interest and then make modifications afterward. Below are functions created for generating child elements and attributes based on an 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);

Answer 3

Answer №2

Successfully resolved the issue utilizing 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);

Answer 4

Successfully resolved the issue utilizing 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);

Generating XML attribute through XPath

Answer №1

Modification

Answer №2

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