Localstorage: Count how many values in key when using stringify

问题

How can I count how many different values I have in 1 localstorage key.

For example:

This is my localstorage:

[{"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 {}..

Is that possible?

回答1:

localStorage is an object, so just localStorage.length gives you the number of entries.

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).length to unserialise the value and count how many there are in there.

回答2:

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:

var something = localstorage.whatever[];
var length = something.length;
alert("length = " + length);

回答3:

This will return the number of items in the key for you

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)

来源：https://stackoverflow.com/questions/8093625/localstorage-count-how-many-values-in-key-when-using-stringify