CODEWITHSUNDEEP
javascripthtmldom
user12251399
user12251399

Reputation:

How To Traverse the DOM and display all tags?

I want to go around the DOM tree, and display all its elements, and their plots. I am stuck with this solution, but it is bad. I need to make a recursive function, but I'm not good at it.

Result of program 

const First = document.querySelector("*");
  for (var i = 0; i < First.children.length; i++) {
      console.log(First.children[i]);
  for (var j = 0; j < First.children[i].children.length; j++) {
    if (First.nodeType == 1) {
       console.log(First.children[i].children[j]);
    }
  }
}
<!DOCTYPE html>
<html lang="en">
<head>
    <meta charset="UTF-8">
    <meta name="viewport" content="width=device-width, initial-scale=1.0">
    <meta http-equiv="X-UA-Compatible" content="ie=edge">
    <title>Document</title>
</head>
<body>
  <h1>Header</h1>
  <p>Some text
     <a href="#">References</a>
  </p>
  <ul id="myList">
    <li>One</li>
    <li>Two</li>
    <li>Tree</li>
  </ul>
</body>
</html>

Upvotes: 1

Views: 68

Answers (2)

kockburn
kockburn

Reputation: 17646

Here is a recuvsive implementation that checks each "parent" element to see if it has more than 0 children. If so loop through the children and call the function and set the "new" parent.

function recursiveTagLister(parent = document.body, depth = 0){
  const indentation = (new Array(depth)).fill('&nbsp;').join("");
  console.log(indentation + parent.tagName);
  if(parent.children.length > 0){
    Array
    .from(parent.children)
    .forEach(item=>recursiveTagLister(item, depth+1));
  }
}

recursiveTagLister();
<!DOCTYPE html>
<html lang="en">
<head>
    <meta charset="UTF-8">
    <meta name="viewport" content="width=device-width, initial-scale=1.0">
    <meta http-equiv="X-UA-Compatible" content="ie=edge">
    <title>Document</title>
</head>
<body>
  <h1>Header</h1>
  <p>Some text
     <a href="#">References</a>
  </p>
  <ul id="myList">
    <li>One</li>
    <li>Two</li>
    <li>Tree</li>
  </ul>
</body>
</html>

Upvotes: 2

Carsten Massmann
Carsten Massmann

Reputation: 28246

If you use document.querySelectorAll("*") there is no need for a recursion.

I aded a second (indented) solution with the recursive function which I wrote in a "curried" way: the function rtl(ind) actually returns another (anonymous) function with the argument of a parent node:

console.log([...document.querySelectorAll('*')].map(e=>e.nodeName).join(', '));

// for indentation use a modified recursive function 
// as written by kemicofa:

function rtl(ind=''){return function(parent=document.body){
  console.log(ind+parent.tagName);
  if(parent.children.length > 0){[...parent.children].forEach(rtl(ind+'  '));}
}}

rtl()();
<!DOCTYPE html>
<html lang="en">
<head>
    <meta charset="UTF-8">
    <meta name="viewport" content="width=device-width, initial-scale=1.0">
    <meta http-equiv="X-UA-Compatible" content="ie=edge">
    <title>Document</title>
</head>
<body>
  <h1>Header</h1>
  <p>Some text
     <a href="#">References</a>
  </p>
  <ul id="myList">
    <li>One</li>
    <li>Two</li>
    <li>Tree</li>
  </ul>
</body>
</html>

Upvotes: 2

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