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Pros and cons using .insertAdjacentHTML vs .createElement
/**
* There is a pro to using document.createElement() instead of just applying a
* string to the page that gets converted to HTML. When we use the pure string method
* we do not get a link/reference to the actual element that is seen on the page. This
* usually means we have to get the element again to modify it. For example, add an event
* listener
*/
//-----------------------------------------------
// .createElement() + .addEventListener()
//-----------------------------------------------
const button = document.createElement('button');
button.innerText = 'Click me';
// We can add an eventlistener directly to the element before adding it to the page
button.addEventListener('click', function(){
console.log('I get applied to the element');
});
// Add it as a child of the <body>-tag
document.body.appendChild(button);
//-----------------------------------------------
// .insertAdjacentHTML + .addEventListener()
//-----------------------------------------------
/* In the eyes of JavaScript, this is just a pure string.
* the element created with .createElement on the other hand
* is recognized as an element. This button doesn't become a button
* until we add it to the page.
*/
const button = `<button id="toggleMenu"> Click me</button>`;
doucument.body.insertAdjacentHTML('afterbegin', button);
/*
* We need to get the element from the page again if we want to manipulate it
* and if we want to get the element from the page, we need to have some sort of
* identifier. In this case I added a id to easily get it from the page.
*/
const toggleMenuButton = document.querySelector('#toggleMenu');
toggleMenuButton.addEventListener('', function(){
console.log('I am now applied to the element');
});
@StevenLeonCooper
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StevenLeonCooper commented Mar 1, 2022

I had the same concern with messy click handlers but I found an elegant way to get around that. The click handler is actually dead simple, it just reads an attribute on the thing you clicked and then tries to invoke a function with that same name as a callback with the event object. You can then organize these functions however you like. Have a clickHandlers object with named properties that match them or just define them right in the JS file. Here's a sample:

HTML:

<div>
  <button type="button" data-action="sayHi">
    Say Hello
  </button>
  <hr>
  <button type="button" data-action="sayMessage" data-message="Howdy!">
    Say Howdy
  </button>
  <hr>
  <input type="text" id="CustomMessage" size="10" placeholder="Type Here">
  <button type="button" data-action="sayCustom" data-for="#CustomMessage">
    Say a Custom Message
  </button>
</div>

JavaScript:

const clickHandlers = {};

clickHandlers.sayHi = () => {
  alert("Hello");
};

clickHandlers.sayMessage = (src) => {
  let msg = src.dataset.message ?? "No Message!";
  alert(msg);
};

clickHandlers.sayCustom = (src) =>{
	let selector = src.dataset.for ?? "body";
  let text = document.querySelector(selector).value;
  alert(text);
};

document.addEventListener("click", (e) => {

  let source = e.target;
  let action = source.dataset.action;
  clickHandlers[action]?.(source, e);
});

That's an over-simplified version but it demonstrates how you can think about the "One Delegate to Rule them All" pattern.

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