import * as sdk from 'matrix-js-sdk';
const createClient = async () => {
try {
const clientOptions = {
baseUrl: MATRIX_SERVER,
};
matrixClient = sdk.createClient(clientOptions);
console.log(matrixClient, 'matrix Client');
isCreated = true;
return true;
} catch (error) {
console.error('Error while creating client:', error);
return false;
}
};

const connect = async () => {
    try {
        if (!isCreated) {
            await createClient();
        }
        await matrixClient.startClient({ initialSyncLimit: 100000 });
        isConnected = true;
        return isConnected;
    } catch (error) {
        console.error('Error while connecting:', error);
        isConnected = false;
        return isConnected; // Return false to indicate that the connection failed.
    }
};

const checkSyncedClient = async (setClientSynced) => {
    setTimeout(() => {
        matrixClient.once('sync', function (state, prevState, res) {
            if (state === 'PREPARED') {
                console.log('account data prepared');
                setClientSynced();
            }
            if (state === 'ERROR') {
                checkSyncedClient(setClientSynced);
            }
        });
    }, 2000);
};

I am using these methods initially to setup Matrix Client.

In reply to @daedric:aguiarvieira.pt
I just died a little..