浏览器刷新后如何使本地存储数据留在页面上

Question

I am currently creating a todo app that allows the user to input info into the form and after submission, the information shows up as a bulleted list item. I have made it so that each submission is saved to localStorage, but how can I also maintain the list item on the page after the browser is refreshed?

here is my JS

const submitButton = document.querySelector('#stuff');
const ul = document.querySelector('ul')
const text = document.querySelector('#textbox');
const todoArr = []
// const todoArr = localStorage.getItem('todos') ? JSON.parse(localStorage.getItem('todos')):[]



submitButton.addEventListener('submit', function(e){
    e.preventDefault();
    if(text.value !== '') {
        const addLi = document.createElement('li');
        const deleteBtn = document.createElement('button');
        deleteBtn.innerText = 'remove';
        addLi.innerText = text.value;
        addLi.appendChild(deleteBtn);
        ul.appendChild(addLi);
        // todoArr.push(text.value)
        localStorage.setItem('todos', JSON.stringify(todoArr))
        text.value = '';
    }
})

ul.addEventListener('click', function(e) {
    if(e.target.tagName === 'BUTTON') {
        e.target.parentElement.remove();
    } else if(e.target.tagName === 'LI'){
        e.target.classList.toggle('strike-thru')
    }
})

Answer 1

Use the code where you create a new list item for your list and put it in a separate function. Let's call that function createTodoItem . When the document loads get the stored todo items from the localStorage and loop over each value. Then with each value call the createTodoItem and pass the value to create a new item.

const submitButton = document.querySelector('#stuff');
const ul = document.querySelector('ul')
const text = document.querySelector('#textbox');

const storedTodos = localStorage.getItem('todos')
const todoArr = storedTodos !== null ? JSON.parse(storedTodos) : [];

function createTodoItem(value) {
  const addLi = document.createElement('li');
  const deleteBtn = document.createElement('button');
  deleteBtn.innerText = 'remove';
  addLi.innerText = value;
  addLi.appendChild(deleteBtn);
  ul.appendChild(addLi);
}

todoArr.forEach(createTodoItem);

Also modify your submit listener to use the new function. Now you've got reusables functions that you can call anywhere in your script.

submitButton.addEventListener('submit', function(e){
    e.preventDefault();
    if(text.value !== '') {
        createTodoItem(text.value);
        todoArr.push(text.value)
        localStorage.setItem('todos', JSON.stringify(todoArr))
        text.value = '';
    }
})

ul.addEventListener('click', function(e) {
    if(e.target.tagName === 'BUTTON') {
        e.target.parentElement.remove();
    } else if(e.target.tagName === 'LI'){
        e.target.classList.toggle('strike-thru')
    }
})