问题描述
在localStorage中存储布尔值，这个值被转换为字符串.现在尝试将此值从 localStorage 转换回布尔值，我需要使用 JSON.parse() 方法，更方便的 !! 不起作用.
Storing boolean value in localStorage, this value is converted to string.
Now trying to converting back this value from localStorage to boolean, i need to use JSON.parse() method, the more handy !! doesn't work.
代码示例:
var test = false;
localStorage['test'] = test;
console.log("JSON.parse returns: ", JSON.parse(localStorage['test']), "expected: ", test);
console.log("'!!' returns: ", !! localStorage['test'], "expected: ", test);
-jsFiddle-
我很困惑为什么会出现这种行为.有什么解释吗?
I'm quite confused why this behaviour. Any explaination?
PS:在这里使用 getter/setter localStorage 方法无关紧要，结果相同.
PS: using getter/setter localStorage methods doesn't matter here, same result.
推荐答案
本地存储存储字符串，恐怕不管输入是什么(如果你用一个对象喂它，它会自动转换成它的标准toString() 方法)...所以你在做 !!在字符串上测试，它总是true.
Local storage stores strings , I'm afraid, whatever the input (if you feed it with an object, it will be converted automatically with its standard toString() method)... So you're doing !! test on a string, which is always true.
在处理 DOM 存储
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