javascript Localstorage：在使用 stringify 时计算 key 中有多少个值
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Localstorage: Count how many values in key when using stringify
提问by jQuerybeast
How can I count how many different values I have in 1 localstorage key.
我如何计算 1 个本地存储键中有多少个不同的值。
For example:
例如：
This is my localstorage:
这是我的本地存储：
[{"id":"item-1","icon":"google.com"},{"id":"item-2","icon":"youtube.com"}]
For this example I'd like an alert of 2 different values. So basically I want to count the {}..
对于此示例，我想要 2 个不同值的警报。所以基本上我想计算{}..
Is that possible?
那可能吗？
回答by Niet the Dark Absol
localStorageis an object, so just localStorage.lengthgives you the number of entries.
localStorage是一个对象，所以只localStorage.length给你条目的数量。
However I think I might be misunderstanding you. Do you mean you have one key, and that key's value is a JSON.stringify'd object? If so, you could do JSON.parse(localStorage.keyname).lengthto unserialise the value and count how many there are in there.
不过我想我可能误解了你。你的意思是你有一个键，那个键的值是一个JSON.stringify'd 对象吗？如果是这样，您可以JSON.parse(localStorage.keyname).length对值进行反序列化并计算其中有多少。
回答by Kevin Anthony Oppegaard Rose
Your object is saved as an array so just using the .length should give you the number of {} pairs you have. Try this (replace "whatever" with the name of your array:
您的对象保存为数组，因此只需使用 .length 即可获得您拥有的 {} 对数。试试这个（用你的数组名替换“whatever”：
var something = localstorage.whatever[];
var length = something.length;
alert("length = " + length);
回答by Graeme Leighfield
This will return the number of items in the key for you
这将为您返回密钥中的项目数
testing = JSON.parse(localStorage.getItem(KEYNAMEHERE));
//Lets count how many we have back
obj = eval('(' + testing + ')');
//And the total is...
objCount=0;
for(_obj in obj) objCount++;
alert(objCount)
