我如何检查一个项目是否设置在localStorage?目前我正在使用
if (!(localStorage.getItem("infiniteScrollEnabled") == true || localStorage.getItem("infiniteScrollEnabled") == false)) {
// init variable/set default variable for item
localStorage.setItem("infiniteScrollEnabled", true);
}
当前回答
我在我的项目中使用过，对我来说非常适合
var returnObjName= JSON.parse(localStorage.getItem('ObjName'));
if(returnObjName && Object.keys(returnObjName).length > 0){
//Exist data in local storage
}else{
//Non Exist data block
}
其他回答
你可以使用hasOwnProperty方法来检查
> localStorage.setItem('foo', 123)
undefined
> localStorage.hasOwnProperty('foo')
true
> localStorage.hasOwnProperty('bar')
false
适用于当前版本的Chrome(Mac)， Firefox(Mac)和Safari。
试试这段代码
if (localStorage.getItem("infiniteScrollEnabled") === null) {
} else {
}
WebStorage规范中的getItem方法，如果项不存在，则显式返回null:
．.． 如果给定的键在与该对象关联的列表中不存在，则该方法必须返回null. ...
所以，你可以:
if (localStorage.getItem("infiniteScrollEnabled") === null) {
//...
}
请看这个相关问题:
在HTML5 localStorage中存储对象
我在这里添加了一些方法来检查
方法1
if("infiniteScrollEnabled" in localStorage){
console.log("Item exists in localstorage");
}else{
console.log("Item does not exist in localstoarge";
}
方法2
if(localStorage.getItem("infiniteScrollEnabled") === null){
console.log("Item does not exist in localstoarge";
}else{
console.log("Item exists in localstorage");
}
方法3
if(typeof localStorage["cart"] === "undefined"){
console.log("Item does not exist in localstoarge";
}else{
console.log("Item exists in localstorage");
}
方法4
if(localStorage.hasOwnProperty("infiniteScrollEnabled")){
console.log("Item exists in localstorage");
}else{
console.log("Item does not exist in localstoarge";
}
最短的方法是使用默认值，如果key不在存储中:
var sValue = localStorage['my.token'] || ''; /* for strings */
var iValue = localStorage['my.token'] || 0; /* for integers */
