Develop Reference

Javascript Split innerText and wrap with a Span

I'm trying to get the inner text of a header, then I would like to split the characters, then wrap each character in a span. I tried previously using insertBefore but I couldn't get it to work.
Here is my current code, which so far just logs each character.
// Title Split
const titleSplit = document.querySelectorAll('.title-split');
// Each El
Array.prototype.forEach.call(titleSplit, function(el, i) {
let innerText = el.innerText;
el.setAttribute('data-word', innerText);
const chars = innerText.split('');
Array.prototype.forEach.call(chars, function(el, i) {
console.log(el);
});
});
I specifically don't want any jQuery solutions. I'm trying to reverse learn Javascript to become more efficient. Any advise would be great. I tried putting in an insertBefore in the chars forEach but it just kept saying undefined.

document.querySelectorAll(...) return a NodeList which contains a method named .forEach(). So Instead of
Array.prototype.forEach.call(titleSplit, function(el, i) {
...
}
You can just do
titleSplit.forEach(...);
Similarly, you can just do
chars.forEach(...);
because chars is an array and you can call .forEach() method on an array.
Now coming to your question, once you have the chars array, you can use .map() method instead of .forEach(), to get a new array that contains strings where each character is wrapped by span tags.
const result = chars.map(c => `<span>${c}</span>`);
Finally, you need to iterate over the result array and insert its elements in the DOM.
result.forEach(el => document.body.append(el));
I have used document.body as the parent element of all the span elements. You can use any element that needs to be the parent element of all the span elements.

You can use map() inside the forEach() loop to construct the result with span. Also I will recommend you not to use innerText as a variable name as it is property name which can lead to some confusion:
// Title Split
const titleSplit = document.querySelectorAll('.title-split');
// Each El
Array.prototype.forEach.call(titleSplit, function(el, i) {
let ElText = el.innerText;
el.setAttribute('data-word', ElText);
const chars = ElText.split('');
var res = chars.map(function(el, i) {
return `<span>${el}</span>`;
}).join('');
el.innerHTML = res;
});
span{
border: 1px solid red;
padding: 2px;
}
<div class="title-split">Hello there</div>

const myHeader = querySelector('query my header please');
const spans = myHeader.innerText
.split('')
.map((char) => `<span>${char}</span>`)
.join('');
document.querySelector('query element to put them').innerHTML = spans;
// OR
document.querySelector('query element to put them').insertAdjacentHTML('beforeend', spans);
// etc.

Using getElementsByTagName to find all hrefs in a variable

In a variable I'm holding HTML source code, which I obtained from DB. I'd like to search this content through for all the "a href" attributes and list them in a table.
Now I've found here how to search it in a DOM (like below), but how to use it to search within a variable?
var links = document.getElementsByTagName("a").getElementsByAttribute("href");
Got this currently, which is searching by RegEx, but it doesn't work very well:
matches_temp = result_content.match(/\b((?:[a-z][\w-]+:(?:\/{1,3}|[a-z0-9%])|www\d{0,3}[.]|[a-z0-9.\-]+[.][a-z]{2,4}\/)(?:[^\s()<>]+|\(([^\s()<>]+|(\([^\s()<>]+\)))*\))+(?:\(([^\s()<>]+|(\([^\s()<>]+\)))*\)|[^\s`!()\[\]{};:'".,<>?«»“”‘’&quote]))/ig);
In result_content I'm holding that HTML Source.

getElementsByTagName returns a nodelist that does not have a method called getElementsByAttribute but ONLY if you have DOM access
Without DOM (for example node.js)
const hrefRe = /href="(.*?)"/g;
const urlRe = /\b((?:[a-z][\w-]+:(?:\/{1,3}|[a-z0-9%])|www\d{0,3}[.]|[a-z0-9.\-]+[.][a-z]{2,4}\/)(?:[^\s()<>]+|\(([^\s()<>]+|(\([^\s()<>]+\)))*\))+(?:\(([^\s()<>]+|(\([^\s()<>]+\)))*\)|[^\s`!()\[\]{};:'".,<>?«»“”‘’&quote]))/ig;
const stringFromDB = `000
Something something 001 something`
stringFromDB.match(hrefRe).forEach(
(href) => console.log(href.match(urlRe)[0] )
);
// oldschool:
// stringFromDB.match(hrefRe).forEach(function(href) { console.log(href.match(urlRe)[0] ) });
In this code I create a DOM snippet first
Also I ONLY get anchors that have an href to begin with
NOTE the getAttribute so the browser does not try to interpret the URL
With the regex if you wanted to only match SPECIFIC types of href:
const re = /\b((?:[a-z][\w-]+:(?:\/{1,3}|[a-z0-9%])|www\d{0,3}[.]|[a-z0-9.\-]+[.][a-z]{2,4}\/)(?:[^\s()<>]+|\(([^\s()<>]+|(\([^\s()<>]+\)))*\))+(?:\(([^\s()<>]+|(\([^\s()<>]+\)))*\)|[^\s`!()\[\]{};:'".,<>?«»“”‘’&quote]))/ig;
const stringFromDB = `000
001`
let doc = document.createElement("div");
doc.innerHTML = stringFromDB
doc.querySelectorAll("a[href]").forEach(
(x) => console.log(x.getAttribute("href").match(re)[0])
);
Without the regex
const stringFromDB = `000
001`
let doc = document.createElement("div");
doc.innerHTML = stringFromDB
doc.querySelectorAll("a[href]").forEach(
(x) => console.log(x.getAttribute("href"))
);

Firstly, you shouldn't be using RegEx to parse HTML. This answer explains why.
Secondly, you're using getElementsByAttribute incorrectly - it does exactly what it says and gets elements by attributes. You should just use querySelectorAll on all elements with a href, and then map out the hrefs:
var hrefs = document.querySelectorAll("a[href*=http]");
var test = Array.prototype.slice.call(hrefs).map(e => e.href);
console.log(test);
Example
Example 1
Example 2
Example 3

Use loop and find html element's values JavaScript

I want to use vanilla js to loop through a string of html text and get its values. with jQuery I can do something like this
var str1="<div><h2>This is a heading1</h2><h2>This is a heading2</h2></div>";
$.each($(str1).find('h2'), function(index, value) {
/// console.log($(value).text());
});
using $(str) converts it to an html string as I understand it and we can then use .text() to get an element (h2)'s value.
but I want to do this within my node app on the backend rather than on the client side, because it'd be more efficient (?) and also it'd just be nice to not rely on jQuery.
Some context, I'm working on a blogging app. I want a table of contents created into an object server side.

This is another way using .innerHTML but uses the built-in iterable protocol
Here's the operations we'll need, the types they have, and a link to the documentation of that function
Create an HTML element from a text
String -> HTMLElement – provided by set Element#innerHTML
Get the text contents of an HTML element
HTMLElement -> String – provided by get Element#innerHTML
Find nodes matching a query selector
(HTMLElement, String) -> NodeList – provided by Element#querySelectorAll
Transform a list of nodes to a list of text
(NodeList, HTMLElement -> String) -> [String] – provided by Array.from
// html2elem :: String -> HTMLElement
const html2elem = html =>
{
const elem = document.createElement ('div')
elem.innerHTML = html
return elem.childNodes[0]
}
// findText :: (String, String) -> [String]
const findText = (html, selector) =>
Array.from (html2elem(html).querySelectorAll(selector), e => e.textContent)
// str :: String
const str =
"<div><h1>MAIN HEADING</h1><h2>This is a heading1</h2><h2>This is a heading2</h2></div>";
console.log (findText (str, 'h2'))
// [
// "This is a heading1",
// "This is a heading2"
// ]
// :: [String]
console.log (findText (str, 'h1'))
// [
// "MAIN HEADING"
// ]
// :: [String]

The best way to parse HTML is to use the DOM. But, if all you have is a string of HTML, according to this Stackoverflow member) you may create a "dummy" DOM element to which you'd add the string to be able to manipulate the DOM, as follows:
var el = document.createElement( 'html' );
el.innerHTML = "<html><head><title>aTitle</title></head>
<body><div><h2>This is a heading1</h2><h2>This is a heading2</h2></div>
</body</html>";
Now you have a couple of ways to access the data using the DOM, as follows:
var el = document.createElement( 'html' );
el.innerHTML = "<html><head><title>aTitle</title></head><body><div><h2>This is a heading1</h2><h2>This is a heading2</h2></div></body</html>";
// one way
el.g = el.getElementsByTagName;
var h2s = el.g("h2");
for(var i = 0, max = h2s.length; i < max; i++){
console.log(h2s[i].textContent);
if (i == max -1) console.log("\n");
}
// and another
var elementList = el.querySelectorAll("h2");
for (i = 0, max = elementList.length; i < max; i++) {
console.log(elementList[i].textContent);
}
You may also use a regular expression, as follows:
var str = '<div><h2>This is a heading1</h2><h2>This is a heading2</h2></div>';
var re = /<h2>([^<]*?)<\/h2>/g;
var match;
var m = [];
var i=0;
while ( match = re.exec(str) ) {
m.push(match.pop());
}
console.log(m);
The regex consists of an opening H2 tag followed by not a "<",followed by a closing H2 tag. The "*?" take into account zero or multiple instances of which there is at least zero or one instance.
Per Ryan of Stackoverflow:
exec with a global regular expression is meant to be used in a loop,
as it will still retrieve all matched subexpressions.
The critical part of the regex is the "g" flag as per MDN. It allows the exec() method to obtain multiple matches in a given string. In each loop iteration, match becomes an array containing one element. As each element is popped off and pushed onto m, the array m ultimately contains all the captured text values.

Insert array of elements into the DOM? [duplicate]

This question already has answers here:
Javascript - efficiently insert multiple HTML elements
(3 answers)
Closed 5 years ago.
I have an array of elements:
const itemCurrent = document.createElement('div');
const itemNext = document.createElement('div');
Ive created an array of them:
const itemsAll = [itemCurrent, itemNext];
How can I insert all of them into the body of my page?

You may simply use .append() to append multiple DOM nodes all at once as follows;
var divs = Array.from({length:10}) // lets make an array of 10 divs
.map(function(_,i){
var el = document.createElement('div');
el.textContent = `I am div # ${i}`;
return el;
});
document.body.append(...divs);
In fact the above snippet has some redundany since Array.from() bears built in mapping. So the following rephrased code would be more reasonable.
var divs = Array.from( {length:10} // lets make an array of 10 divs
, function(_,i){ // and map it accordingly
var el = document.createElement('div');
el.textContent = `I am div # ${i}`;
return el;
}
);
document.body.append(...divs);

To add the elements to the body, you need to append them to the body of your document. This is done by using the appendChild(element) function :
// looping through your array :
for (let i=0;i<itemsAll.length;i++) {
// appending your elements to the body :
document.body.appendChild(itemsAll[i]);
}

To recollect what others have said:
in JS, you iterate over an array with array.forEach which takes one argument - a function that will be called on all the elements of the array sequentially
to append (add at the end) an element to the DOM (body of the page) you call document.body.appendChild which takes the element to be added as an argument
Code you need then becomes
itemsAll.forEach(function (element, index, array) {
document.body.appendChild(element);
})
or (using ES6 syntax)
itemsAll.forEach(el => document.body.appendChild(el))

Iterating over array and appending each using appendChild:
itemsAll.forEach(el => {
document.body.appendChild(el)
})

Assigning javascript array elements class or id for css styling

I'm trying to assign class and id to items in an array I created in js and input into my html. I'm doing this so I can style them in my stylesheet. Each item will not be styled the same way.
I'm a beginner so trying to keep it to code I can understand and make it as clean as possible, i.e. not making each of these items an element in the html.
This part works fine:
var pool =['A','B','3','J','R','1','Q','F','5','T','0','K','N','C','R','U']
var letters = pool.join('');
document.getElementById('key').innerHTML = letters;
This part not so much:
var char1 = letters[1];
char1.classList.add('hoverRed');
There is a similar question here that didn't work for me, it just showed [object][object][object] when I ran it.

Your code attempts to apply a style to an array element, but CSS only applies to HTML. If you wish to style one character in a string, that character must be wrapped in an HTML element (a <span> is the best choice for wrapping an inline value).
This code shows how to accomplish this:
var pool =['A','B','3','J','R','1','Q','F','5','T','0','K','N','C','R','U']
var letters = pool.join('');
// Replace a specific character with the same character, but wrapped in a <span>
// so it can be styled
letters = letters.replace(letters[1], "<span>" + letters[1] + "</span>");
// Insert the letters string into the div
var theDiv = document.getElementById('key');
// Inject the string into the div
theDiv.innerHTML = letters;
// Get a reference to the span:
var theSpan = theDiv.querySelector("span");
// Add the style to the <span> that wraps the character, not the character itself
theSpan.classList.add('hoverRed');
.hoverRed {
color:red;
}
<div id="key"></div>
And, this snippet shows how you could apply CSS to any letter:
var pool =['A','B','3','J','R','1','Q','F','5','T','0','K','N','C','R','U'];
// Leave the original array alone so that it can be manipulated any way needed
// in the future, but create a new array that wraps each array element within
// a <span>. This can be accomplished in several ways, but the map() array method
// is the most straight-forward.
var charSpanArray = pool.map(function(char){
return "<span>" + char + "</span>";
});
// Decide which character(s) need CSS applied to them. This data can come from anywhere
// Here, we'll just say that the 2nd and 5th ones should.
// Loop through the new array and on the 2nd and 5th elements, apply the CSS class
charSpanArray.forEach(function(element, index, array){
// Check for the particular array elements in question
if(index === 1 || index === 4){
// Update those strings to include the CSS
array[index] = element.replace("<span>","<span class='hoverRed'>");
}
});
// Now, turn the new array into a string
var letters = charSpanArray.join('');
// For diagnostics, print the string to the console just to see what we've got
console.log(letters);
// Get a reference to the div container
var theDiv = document.getElementById('key');
// Inject the string into the div
theDiv.innerHTML = letters;
.hoverRed {
color:red;
}
<div id="key"></div>

You're on the right track, but missed one key thing.
In your example, pool contains characters. When you combine them using join, you get a string. Setting that string as the innerHTML of an element doesn't give the string super powers, it's still just a string.
In order to get a classList, you need to change your letters into elements and work with them.
I've included an es6 example (and a working plunker) of how to get the functionality you want below.
let pool = ['A','B','3','J','R','1','Q','F','5','T','0','K','N','C','R','U']
const letterToElement = function(char) {
//Create the element
let e = document.createElement("SPAN");
//Create the text node
let t = document.createTextNode(char);
//Put the text node on the element
e.appendChild(t);
//Add the class name you want
e.className += "hoverRed";
return e;
};
//create your elements from your pool and append them to the "key" element
window.onload = function() {
let container = document.getElementById("key");
pool.map(l => letterToElement(l))
.forEach(e => container.appendChild(e));
}
https://plnkr.co/edit/mBhA60aUCEGSs0t0MDGu