Save an array of Items in AsyncStorage

Question

How can I save an array of Items with AsyncStorage in react-native? So that every time you add another contact to your list it keeps adding up and not rewriting

Code:

saveContacts = ()=> {
    try {
        let con = {
            roomId: this.state.roomId,
            nickname: this.state.nickname,
        }
        AsyncStorage.setItem('contacts', JSON.stringify(con));
    }catch(error) {
        alert(error)
    }
}

Matt Aft · Accepted Answer · 2017-12-20 20:49:14Z

13

You can retrieve the contacts and concat the new contact to the list, then set it back into storage. Just make sure to initially set it as an empty array:

AsyncStorage.getItem('contacts')
  .then((contacts) => {
    const c = contacts ? JSON.parse(contacts) : [];
    c.push(con);
    AsyncStorage.setItem('contacts', JSON.stringify(c));
  });

edited Dec 20, 2017 at 20:49

answered Dec 20, 2017 at 1:22

Matt Aft

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3 Comments

I'm not human Over a year ago

I get " Possible Unhandled Promise Rejection (id: 0): TypeError: JSON.parse(contacts).concat is not a function. (In 'JSON.parse(contacts).concat(con)', 'JSON.parse(contacts).concat' is undefined) "

Matt Aft Over a year ago

Updated my answer.

Wittner Over a year ago

await AsyncStorage.getItem('contacts') ?

jkhedani · Accepted Answer · 2017-12-20 01:34:52Z

1

Get and set your records into an array then save to AsyncStorage:

saveContacts = async () => {
    try {
        let con = {
            roomId: this.state.roomId,
            nickname: this.state.nickname,
        }
        const contacts = await AsyncStorage.getItem('contacts') || '[]';
        contacts = JSON.parse(contacts);
        contacts.push(con);
        AsyncStorage.setItem('contacts', JSON.stringify(contacts)).then(() => {
            console.log('Contacts updated.')
        });
    } catch(error) {
        alert(error)
    }
};

answered Dec 20, 2017 at 1:34

jkhedani

4683 silver badges11 bronze badges

5 Comments

I'm not human Over a year ago

I get " [TypeError: contacts.push is not a function. (In 'contacts.push(con)', 'contacts.push' is undefined)] "

jkhedani Over a year ago

This probably means that your assigning something other than an array to contacts. make sure the AsynStorage item 'contacts' is indeed an array and this will work.

I'm not human Over a year ago

Isn't contacts supposed to be that const variable? By the way I had to change it to let variable because if it's constant you cant do the 2 lines beneath.

jkhedani Over a year ago

Contacts is the variable and should be an array before you push anything to it. Otherwise, you'll end up with the error you are getting. It's the same reason the answer below is failing. I would log const contacts = await AsynStorage.getItem('contacts') and see what it returns.

DevAS Over a year ago

@jkhedani Hey, If I wanna just log the RoomID when i getItem from Storage, How to handle that?

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