index.js

let myLeads = []
const inputEl = document.getElementById("input-el");
const inputBtn = document.getElementById("input-btn");
const ulEl = document.getElementById("ul-el")
const deleteBtn = document.getElementById("delete-btn")
const tabBtn = document.getElementById("tab-btn")
const leadsFromStorage = JSON.parse(localStorage.getItem("myLeads"));

if(leadsFromStorage){
    myLeads = leadsFromStorage;
    render(myLeads);
}

tabBtn.addEventListener("click", function(){    
    chrome.tabs.query({active: true, currentWindow: true}, function(tabs){
        myLeads.push(tabs[0].url)
        localStorage.setItem("myLeads", JSON.stringify(myLeads) )
        render(myLeads)
    })
})


function render(leads){
    let listItems = ""
    for (let i = 0; i < leads.length; i++) {
        listItems += `<li>
                        <a href='${leads[i]}' target=blank>${leads[i]}</a>
                      </li>`
    }
    ulEl.innerHTML = listItems  
}

deleteBtn.addEventListener("dblclick", function(){
    localStorage.clear()
    myLeads = []
    render("")
})

inputBtn.addEventListener("click", function(){
    myLeads.push(inputEl.value)
    inputEl.value = ""
    localStorage.setItem("myLeads", JSON.stringify(myLeads) )
    render(myLeads)
})