javascript - 如何检查存储项是否已设置？(How to check whether a Storage item is set?)

Question

How can I check if an item is set in localStorage ?(如何检查localStorage是否设置了项目？)

Currently I am using(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);
}

  ask by Jiew Meng translate from so

Answer 1

The getItem method in the WebStorage specification, explicitly returns null if the item does not exist:(WebStorage规范中的getItem方法，如果该项不存在，则显式返回null ：)

... If the given key does not exist in the list associated with the object then this method must return null.(...如果给定键与对象关联的列表中不存在，则此方法必须返回null。)

...(...)

So, you can:(所以你可以：)

if (localStorage.getItem("infiniteScrollEnabled") === null) {
  //...
}

See this related question:(看到这个相关的问题：)

• Storing Objects in HTML5 localStorage(在HTML5 localStorage中存储对象)