custom web component event call back function in tag

Question

class UioKey extends HTMLElement {
 ...
 eKey(){windows.alert('class  eKey function')}
 
 
 }
 
 function eKey(){
 eKey(){windows.alert('document eKey function')}

<template id="uio-key-temp">
    <div class="uio-key">
         <div class="i" onclick="eKey()"></div><span></span>
    </div>
</template>    

when clikcing on the .i div agot the document ekey that is firing, i want the class ekey() to be fired if i omit the dodument eKey() fuction i got function eKey() undefined

Answer 1

onclick will only work with globally defined functions.

Here is a very quick hack that allows you to use a class function.

// Class for `<uio-key>`
class UioKey extends HTMLElement {
  constructor() {
    super();

    let shadow = this.attachShadow({mode: 'open'});
    shadow.innerHTML = '<div><div on-click="eKey">div</div><span>span</span></div>';
    let a = shadow.querySelectorAll('[on-click]');
    a.forEach(
      el => {
        const handlerName = el.getAttribute('on-click');
        el.addEventListener('click', this[handlerName]);
      }
    );
  }

  eKey() {
    window.alert('class  eKey function');
  }
}

// Define our web component
customElements.define('uio-key', UioKey);

<hr/>
<uio-key></uio-key>
<hr/>

I use a custom attribute on-click as a way to grab all elements that want a click handler then I take the value of that attribute and use it as the class function name and pass it into the addEventListener function.