javascript - 如何使用localStorage保存数据

Question

我正在做待办事项列表，并且将数据保存在todotask行和已完成中。内景 https://jsfiddle.net/6rqfd103/

I tried to save it as an array, I saved it, but couldn't get it outside and this is the code when I haven't done anything, show me how, I don't understand this place yet. explain to me. thank you very much

var newTaskInput = document.getElementById("new-task");
var addButton = document.getElementsByTagName("button")[0];
var todoTask = document.getElementById("incomplete-tasks");
var completeTask= document.getElementById("completed-tasks");

var createNewTaskElement = function(taskString) {
  var listItem = document.createElement("li");
  var checkBox = document.createElement("input");
  var label = document.createElement("label");
  var editInput = document.createElement("input");
  var editButton = document.createElement("button");
    var deleteButton = document.createElement("button");

  checkBox.type = "checkbox";
  editInput.type = "text";
  editButton.innerText = "Edit";
  editButton.className = "edit";
  deleteButton.innerText = "Delete";
  deleteButton.className = "delete";

  label.innerText = taskString;

  listItem.appendChild(checkBox);
  listItem.appendChild(label);
  listItem.appendChild(editInput);
  listItem.appendChild(editButton);
  listItem.appendChild(deleteButton);

  return listItem;
}

var addTask = function() {
    if(newTaskInput.value == ""){
        alert("Nhap todoTask Item !");
        return false;
    }
  var listItem = createNewTaskElement(newTaskInput.value);
  todoTask.appendChild(listItem);
  bindTaskEvents(listItem, taskCompleted);

    newTaskInput.value = "";
    return true;
}

var editTask = function() {
  var listItem = this.parentNode;
  var editInput = listItem.querySelector("input[type=text");
  var label = listItem.querySelector("label");
    var containsClass = listItem.classList.contains("editMode");

  if(containsClass) {
    label.innerText = editInput.value;
  } else {
    editInput.value = label.innerText;
  }
  listItem.classList.toggle("editMode");  
}

var deleteTask = function() {
  var listItem = this.parentNode;
  var ul = listItem.parentNode;

  ul.removeChild(listItem);
}

var taskCompleted = function() {
  var listItem = this.parentNode;
  completeTask.appendChild(listItem);
  bindTaskEvents(listItem, taskIncomplete);
}

var taskIncomplete = function() {
  var listItem = this.parentNode;
  todoTask.appendChild(listItem);
  bindTaskEvents(listItem, taskCompleted);
}

var bindTaskEvents = function(taskListItem, checkBoxEventHandler) {
  console.log("Bind list item events");
  var checkBox = taskListItem.querySelector("input[type=checkbox]");
  var editButton = taskListItem.querySelector("button.edit");
  var deleteButton = taskListItem.querySelector("button.delete");

  editButton.onclick = editTask;

  deleteButton.onclick = deleteTask;

  checkBox.onchange = checkBoxEventHandler;
}

addButton.addEventListener("click", addTask);

for(var i = 0; i < todoTask.children.length; i++) {
  bindTaskEvents(todoTask.children[i], taskCompleted);
}

for(var i = 0; i < completeTask.children.length; i++) {
  bindTaskEvents(completeTask.children[i], taskIncomplete);
}

Answer 1

如果您正在测试/使用 Google Chrome，您可以使用 localStorage.setItem() 和 localStorage.getItem()。 .setItem() 创建一个保存到本地存储的对象。该方法接受两个参数，第一个是字符串格式的对象名称(选择您想要的任何名称)，第二个是要进入对象内部的值。您提到您正在使用数组作为返回的项目， .setItem() 第二个参数可以采用数组。有一个细微差别，数据必须采用 JSON 格式。下面的例子。

const myArray = [1, 2, 3];
const myArrayToJson = JSON.stringify(myArray);
localStorage.setItem('myObjectName', myArrayToJson);

现在，当您刷新页面时，无论在代码中的何处将应用程序呈现到网页，您都需要使用 .getItem 方法，该方法采用一个参数。该参数是您上面创建的对象的名称。然后，您解析数据并在任何您想要的地方调用或渲染它。

const myFetchedArrayInJson = localStorage.getItem('myObjectName');
const myFetchedArrayParsed = JSON.parse(myFetchedArrayInJson);
--- Now do something with it.

希望这有帮助!