134

So, I was thinking I could just loop through localStorage like a normal object as it has a length. How can I loop through this?

localStorage.setItem(1,'Lorem');
localStorage.setItem(2,'Ipsum');
localStorage.setItem(3,'Dolor');

If I do a localStorage.length it returns 3 which is correct. So I'd assume a for...in loop would work.

I was thinking something like:

for (x in localStorage){
    console.log(localStorage[x]);
}

But no avail. Any ideas?

The other idea I had was something like

localStorage.setItem(1,'Lorem|Ipsum|Dolor')
var split_list = localStorage.getItem(1).split('|');

In which the for...in does work.

1

10 Answers 10

176

You can use the key method. localStorage.key(index) returns the indexth key (the order is implementation-defined but constant until you add or remove keys).

for (var i = 0; i < localStorage.length; i++){
    $('body').append(localStorage.getItem(localStorage.key(i)));
}

If the order matters, you could store a JSON-serialized array:

localStorage.setItem("words", JSON.stringify(["Lorem", "Ipsum", "Dolor"]));

The draft spec claims that any object that supports structured clone can be a value. But this doesn't seem to be supported yet.

EDIT: To load the array, add to it, then store:

var words = JSON.parse(localStorage.getItem("words"));
words.push("hello");
localStorage.setItem("words", JSON.stringify(words));
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10 Comments

Thanks a lot! This is just what I was looking for. Im going to look into the JSON thing you sent also. Thatd be perfect. It's for a Baby Names Offline HTML5 iOS app.
Quick question, how would I add to that JSON? Like, how would I add "hello" after "Dolor"?
you rock, just looking at, it should work. Is there a reason I should use parse and not eval? I'm using eval now to get it from a string, but is parse better/faster?
@Oscar, parse is more secure because it protects you from code execution. And often, it's also much faster. See blog.mozilla.com/webdev/2009/02/12/native-json-in-firefox-31
@BBagi, it returns whatever the input is, decoded. The top level of a JSON text can be an object or array. Try JSON.parse('["Lorem", "Ipsum", "Dolor"]').length
|
65

The simplest way is:

Object.keys(localStorage).forEach(function(key){
   console.log(localStorage.getItem(key));
});

2 Comments

This worked for me. using $.each(localStorage, function(key, value) for some reason included the localStorage functions (i.e cleaR) in the key list.
@TheoretiCAL Probably because you've overwritten the prototype.
24

In addition to all the other answers, you can use $.each function from the jQuery library:

$.each(localStorage, function(key, value){

  // key magic
  // value magic

});

Eventually, get the object with:

JSON.parse(localStorage.getItem(localStorage.key(key)));

3 Comments

This only works if you are using jQuery. $ is used for other libraries and is also often used as an alias for document.querySelectorAll. The question is also not tagged as a [jquery] question.
fails on build in key 'functions' like 'clear' etc...
2024, jquery 1.12: it will iter method
15
for (const [key, value] of Object.entries(localStorage)) {
   console.log(key, value);
}

Here we are looping through each key and value respectively in local storage.

Comments

9

This works for me in Chrome:

for(var key in localStorage) {
  $('body').append(localStorage.getItem(key));
}

9 Comments

Which part exactly? This snippet uses jQuery as per original question. Can you try this in chrome js console? for(var key in localStorage) { console.log(localStorage.getItem(key)); }
@jtblin I just tried it, it returned TypeError: Cannot call method 'toString' of null, so I assume 'key' is returning null
This works in recent versions of Chrome, Safari and Firefox
@JuanCarlosAlpizarChinchilla there is no 'toString' in the code so ¯_(ツ)_/¯. As pointed in comment above, works fine in all recent browsers.
@jtblin my comment is two years old, so ¯_(ツ)_/¯ thanks for the head up though
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4

Building on the previous answer here is a function that will loop through the local storage by key without knowing the key values.

function showItemsByKey() {
   var typeofKey = null;
   for (var key in localStorage) {
       typeofKey = (typeof localStorage[key]);
       console.log(key, typeofKey);
   }
}

If you examine the console output you will see the items added by your code all have a typeof string. Whereas the built-in items are either functions { [native code] } or in the case of the length property a number. You could use the typeofKey variable to filter just on the strings so only your items are displayed.

Note this works even if you store a number or boolean as the value as they are both stored as strings.

Comments

3

localStorage is an Object.

We can loop through it with JavaScript for/in Statement just like any other Object.

And we will use .getItem() to access the value of each key (x).

for (x in localStorage){
    console.log(localStorage.getItem(x));
}

1 Comment

This routine will also return functions, not just properties, which is likely undesirable to most people wanting to get only the property keys and values from localStorage.
2

All of these answers ignore the differences between the implementations of localStorage across browsers. Contributors in this domain should heavily qualify their responses with the platforms they are describing. One browser-wide implementation is documented at https://developer.mozilla.org/en/docs/Web/API/Window/localStorage and, whilst very powerful, only contains a few core methods. Looping through the contents requires an understanding of the implementation specific to individual browsers.

3 Comments

Could you give an example of how one of these answers would not work on a browser? This was a long time ago but I don't remember running into any issues with looping through with these answers
I intended my comment to be added to the overall stream, not this particular post and may have been a bit harsh. I was frustrated at the time trying to find a cross-browser solution. The example by Steve Isenberg (below) containing for (var key in localStorage) { typeofKey = (typeof localStorage[key]); console.log(key, typeofKey); } Doesn't work on webKit implementations (try it!)
This does work: for ( var i = 0; i < localStorage.length; ++i ) { console.log(localStorage.key(i)+":"+ localStorage.getItem(localStorage.key(i))); }
1

The localStorage saves data as key-value pairs and the values can be accessed by the function localStorage.getItem(key), which takes a key as parameter and returns the value of the key-value pair with the given key.

The key-value pairs of the localStorage can be set with the function localStorage.setItem(key, value).

If you want to iterate through the localStorage you can use numbers as keys.

localStorage.setItem(localStorage.length, value);

With this instruction above you are appending a value with an ascending key to the localStorage, because the length of the localStorage is increased by each call.

Now the localStorage can be iterated with the following for-loop.

for (let i = 0; i < localStorage.length; i++){
  console.log(localStorage.getItem(i));
} 

It does not matter if you use "let" or "var" to declare a variable. The difference between both is the scope. If you want to know more about the difference between let and var, I would recommend you the explanation by tutorialspoint (https://www.tutorialspoint.com/difference-between-var-and-let-in-javascript).

Comments

0

Get all the entries with key and value in Array

let entries = Object.entries(localStorage);

console.log(entries);

Comments

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