如何通过存储在本地存储中的索引数组删除数据？

Question

如果我 console.log(localStorage.getItem("cartCache"))，结果是这样的：

{"dataCache":[{"id":20,"quantity":1,"total":100000,"request_date":"27-08-2017 20:31:00"},{"id":53,"quantity":1,"total":200000,"request_date":"27-08-2017 20:38:00"}],"expired":"2017-08-28T03:55:21.521Z"}

我想通过索引数组删除缓存中的数据

例如，当我删除索引数组 = 0 时，结果是这样的：

{"dataCache":[{"id":53,"quantity":1,"total":200000,"request_date":"27-08-2017 20:38:00"}]}

另一个例子，当我删除索引数组 = 1 时，结果是这样的：

{"dataCache":[{"id":20,"quantity":1,"total":100000,"request_date":"27-08-2017 20:31:00"}]}

我该怎么做？

我尝试这样：

var deleteIndex = 1;
var retrievedObj = localStorage.getItem("cartCache")
delete retrievedObj['dataCache'][deleteIndex];

这似乎不是正确的方法

Answer 1

localStorage.getItem("cartCache") 返回两个对象 - dataCache 和 expired。如果要删除dataCache的元素n，通过

删除

localStorage.getItem("cartCache").dataCache.splice(n,1);

要将其放入您的代码中：

var deleteIndex = 1;
var retrievedObj = localStorage.getItem("cartCache");
retrievedObj.dataCache.splice(deleteIndex,1);

然后再次console.log你的localStorage，你会看到元素被删除了。

Answer 2

您可以使用splice 从数组中删除一个项目

// Clearing all localStorage value. No need to use below line in your code
localStorage.clear();
// to be stored object
var x = {
  "dataCache": [{
    "id": 20,
    "quantity": 1,
    "total": 100000,
    "request_date": "27-08-2017 20:31:00"
  }, {
    "id": 53,
    "quantity": 1,
    "total": 200000,
    "request_date": "27-08-2017 20:38:00"
  }],
  "expired": "2017-08-28T03:55:21.521Z"
}
// Initially storing it in local storage using JSON.stringify
localStorage.setItem('storeData', JSON.stringify(x));
// Once stored retrieving the value using JSON.parse
var getItem = JSON.parse(localStorage.getItem('storeData'));
// setting the dataCache with new array. The new array will be created as splice is used. splice is used to remove an item from array,
//0 is the index of the array, while second parameter 1 is to represent how many item to be removed starting from 0 ndex
getItem.dataCache = getItem.dataCache.splice(0, 1);
console.log(getItem); // the modified object
// after operation setting it to local storage
localStorage.setItem('storeData', JSON.stringify(getItem))

DEMO

Answer 3

关键字“delete”仅在retrieveObj 中删除deleteIndex，它不会更新您的localStorage 值。为了更新 localStorage 使用：

var deleteIndex = 1;
var retrievedObj = localStorage.getItem("cartCache")
delete retrievedObj['dataCache'][deleteIndex];
localStorage.setItem("cartCache", retrieveObj)