Copy to clipboard in chrome extension V3

Question

I am developing a chrome extension V3. I want to copy content to clipboard in my JS file.
The manifest.json as below,

    "background" :{
        "service_worker" :"eventPage.js"
    },
    "permissions" : [
        "contextMenus",
        "clipboardWrite"      
    ]

I have try 2 solution for copy feature.

Solution 1:

    const el = document.createElement('textarea');
    el.value = str;
    el.setAttribute('readonly', '');
    el.style.position = 'absolute';
    el.style.left = '-9999px';
    document.body.appendChild(el);
    el.select();
    document.execCommand('copy');
    document.body.removeChild(el);
  

The result:

Error in event handler: ReferenceError: document is not defined at copyToClipboard 

Solution 2:

navigator.clipboard.writeText(str);

The result:

Error in event handler: TypeError: Cannot read properties of undefined (reading 'writeText')

The chrome extension is run as a service worker. So it seems I can't access DOM document and have no grant of writeText. Does anyone have another suggestion?

Thanks.