Update specific value of object in localStorage [duplicate]

Question

I want to update the dataId field of an object in localStorage. Object:

let responseJson = {
                      id: user.id,
                      username: user.username,
                      firstName: user.firstName,
                      dataId: 1000
                   };

I am tring using following code:

let loggedInUser = localStorage.getItem('user_id');
JSON.parse(loggedInUser).userId = parseInt(2000);
localStorage.setItem('user_id', loggedInUser);

Updated:

let loggedInUser = localStorage.getItem('user_id');
loggedInUser.dataId = parseInt(2000);
console.log('loggedInUser', JSON.stringify(loggedInUser));
localStorage.setItem('user_id', JSON.stringify(loggedInUser));

You need to JSON.stringify loggedInUser object when saving to localStorage — Harun Yilmaz
– Harun Yilmaz, Commented Jan 29, 2020 at 8:21
@HarunYilmaz Yeah I updated my code but still there is no value changed in localStorage — Varinder Sohal
– Varinder Sohal, Commented Jan 29, 2020 at 8:25
You're not modifying the loggedInUser value, you're modifying the parsed value, which is should be assigned to a variable, and then reencoded. — FMCorz
– FMCorz, Commented Jan 29, 2020 at 8:27

Merci Dieu KIMPOLO · Accepted Answer · 2020-01-29 09:20:05Z

3

This can help:

let responseJson = {
                      id: user.id,
                      username: user.username,
                      firstName: user.firstName,
                      dataId: 1000
                   };

let loggedInUser = JSON.parse(localStorage.getItem('user_id'));
loggedInUser.dataId = parseInt(2000);
localStorage.setItem('user_id', JSON.stringify(loggedInUser));

edited Jan 29, 2020 at 9:20

answered Jan 29, 2020 at 8:24

Merci Dieu KIMPOLO

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7 Comments

Varinder Sohal Over a year ago

its not working

Merci Dieu KIMPOLO Over a year ago

Hello @VarinderSohal, what are your getting an error?

Varinder Sohal Over a year ago

can't assign to property "dataId" on {} : not an object

Merci Dieu KIMPOLO Over a year ago

Can you update your code by sharing what you have currently?

Varinder Sohal Over a year ago

Code update has done you can see it

|

MadDeveloper · Accepted Answer · 2020-01-29 08:22:42Z

1

In localStorage, all values must be of type string. So, you have to stringify your object before storing it.

localStorage.setItem('user_id', JSON.stringify(loggedInUser))

BTW: You should check the user_id value before parsing it (or encapsulate in a try/catch).

answered Jan 29, 2020 at 8:22

MadDeveloper

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Comments

Jai · Accepted Answer · 2020-01-29 09:54:49Z

1

You can do something like this and you should stringify it before setting to localStorage:

let loggedInUser = JSON.parse(localStorage.getItem('user_id'));
let loggedInUserObj = {...loggedInUser, dataId : 2000}; // <---should be dataId
localStorage.setItem('user_id', JSON.stringify(loggedInUserObj));

Note:- You are not updating the dataId property but userId.

edited Jan 29, 2020 at 9:54

answered Jan 29, 2020 at 8:23

Jai

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2 Comments

Varinder Sohal Over a year ago

Thankyou for your reply but your code just added new field not updated current available filed.

Jai Over a year ago

@VarinderSohal oh yes. you should parse the string to object before and then destructure it to update. and one thing in your question you have posted to update the userId not dataId.

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