Rather than overwriting it, append a new value to the localstorage

Question

Rather than overwriting it, append a new value to the localstorage

I am trying to insert the value of newUsername into the localStorage setUsernamesArray. However, my current code overwrites the existing value instead of adding to it.

Code

$('#signUpButton').click(function() {
  var newUsername = $('#usernameSignInBox').val();
  signedUpUsernames.push(newUsername);
  localStorage.setItem('setUsernamesArray', signedUpUsernames);
});

javascript jquery html css

Answer 1

Answer №1

To update the array, remember that the data stored in localStorage is a string, not an array. To convert this string into an array and make updates, follow these steps:

Retrieve the string using

localStorage.getItem('setUsernamesArray')

,

Convert the string into an array using JSON.parse,
Add new elements to the array,

Update the localStorage with the modified array using

localStorage.setItem('setUsernamesArray', JSON.stringify(array))

.

Answer 2

To update the array, remember that the data stored in localStorage is a string, not an array. To convert this string into an array and make updates, follow these steps:

Retrieve the string using

localStorage.getItem('setUsernamesArray')

,

Convert the string into an array using JSON.parse,
Add new elements to the array,

Update the localStorage with the modified array using

localStorage.setItem('setUsernamesArray', JSON.stringify(array))

.

Answer 3

Answer №2

localStorage always saves data as a string, so make sure to convert your array into a string using stringify before storing it.

localStorage.setItem('usernamesArray', JSON.stringify(signedUpUsernames));

When retrieving the data, remember to parse it back into an array:

var retrievedArray = JSON.parse(localStorage.getItem("usernamesArray"))

Answer 4

localStorage always saves data as a string, so make sure to convert your array into a string using stringify before storing it.

localStorage.setItem('usernamesArray', JSON.stringify(signedUpUsernames));

When retrieving the data, remember to parse it back into an array:

var retrievedArray = JSON.parse(localStorage.getItem("usernamesArray"))

Answer 5

Answer №3

localStorage.setItem function is used to replace the value of a key in the localStorage.

Think of localStorage as a variable. Just like when you reassign a variable,

var a = "Hello";
a = " World"

the value of a gets replaced. To prevent that, you can use +=

var a = "Hello";
a += " World"

Similarly, when working with localStorage, you need to create a new object with the updated value and then write it back to localStorage.

Here's an example:

function setValueToLS(key, prop, value){
  var _local = {};
  if(localStorage.getItem(key))
    _local = JSON.parse(localStorage.getItem(key));

  _local[prop] = value;

  localStorage.setItem(key, JSON.stringify(_local));
}

Answer 6

localStorage.setItem function is used to replace the value of a key in the localStorage.

Think of localStorage as a variable. Just like when you reassign a variable,

var a = "Hello";
a = " World"

the value of a gets replaced. To prevent that, you can use +=

var a = "Hello";
a += " World"

Similarly, when working with localStorage, you need to create a new object with the updated value and then write it back to localStorage.

Here's an example:

function setValueToLS(key, prop, value){
  var _local = {};
  if(localStorage.getItem(key))
    _local = JSON.parse(localStorage.getItem(key));

  _local[prop] = value;

  localStorage.setItem(key, JSON.stringify(_local));
}

Rather than overwriting it, append a new value to the localstorage

Code

Answer №1

Answer №2

Answer №3

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