published: 09 Jul 2022
2 min read
Iterating over all keys stored in local storage using JavaScript
There are many ways to iterate through all keys stored in a localStorage object using JavaScript.
The quickest way is to use the for loop to iterate over all keys just like an array:
for (let i = 0; i < localStorage.length; i++) {
const key = localStorage.key(i)
console.log('${key}: ${localStorage.getItem(key)}')
}
Another way is to use the for...in loop to iterate over all keys of the localStorage object:
for (const key in localStorage) {
console.log('${key}: ${localStorage.getItem(key)}')
}
The above code snippet iterates over all keys stored in localStorage and prints them on the console. However, it also outputs the built-in localStorage properties like length, getItem, setItem, and so on.
To filter-out the object prototype's own properties, you can use the hasOwnProperty() method as shown below:
for (const key in localStorage) {
// Skip built-in properties like length, setItem, etc.
if (localStorage.hasOwnProperty(key)) {
console.log('${key}: ${localStorage.getItem(key)}')
}
}
Finally, the last way is to use the Object.keys() method to collect all 'own' keys of localStorage and then loop over them by using the for...of loop:
const keys = Object.keys(localStorage)
for (let key of keys) {
console.log('${key}: ${localStorage.getItem(key)}')
}
Read this article to learn more about HTML web storage API and how to use localStorage and sessionStorage objects to store information in the user's browser.
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Iterating over all keys stored in local storage using JavaScript
There are many ways to iterate through all keys stored in a localStorage object using JavaScript.
The quickest way is to use the for loop to iterate over all keys just like an array:
for (let i = 0; i < localStorage.length; i++) {
const key = localStorage.key(i)
console.log('${key}: ${localStorage.getItem(key)}')
}
Another way is to use the for...in loop to iterate over all keys of the localStorage object:
for (const key in localStorage) {
console.log('${key}: ${localStorage.getItem(key)}')
}
The above code snippet iterates over all keys stored in localStorage and prints them on the console. However, it also outputs the built-in localStorage properties like length, getItem, setItem, and so on.
To filter-out the object prototype's own properties, you can use the hasOwnProperty() method as shown below:
for (const key in localStorage) {
// Skip built-in properties like length, setItem, etc.
if (localStorage.hasOwnProperty(key)) {
console.log('${key}: ${localStorage.getItem(key)}')
}
}
Finally, the last way is to use the Object.keys() method to collect all 'own' keys of localStorage and then loop over them by using the for...of loop:
const keys = Object.keys(localStorage)
for (let key of keys) {
console.log('${key}: ${localStorage.getItem(key)}')
}
Read this article to learn more about HTML web storage API and how to use localStorage and sessionStorage objects to store information in the user's browser.
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JS Nooby
Javascript connoisseur
