Migrate from v4 to e3kit-js v0.4.1

index.js

// to load private keys created with sdk v4, you can use the `KeyStorage` class from sdk v5 - https://github.com/VirgilSecurity/virgil-sdk-javascript/blob/master/src/Storage/KeyStorage.ts
// (ignore the deprecation warning)
// note, if you used the default key storage name with sdk v4 (i.e. didn't provide `keyStorageName` option to the `API` function), 
// then you will have to provide a `name` config parameter equal to "VirgilSecurityKeys"  into the `KeyStorage` constructor - `new KeyStorage({ name: "VirgilSecurityKeys" })`
// otherwise, provide the same value as you did for the `keyStorageName` option

// One caveat is that the `KeyStorage` from v5 sdk only uses IndexedDB as a storage backend, whereas in v4 we used the localforage (https://github.com/localForage/localForage)
// library, which aslo uses IndexedDB, but falls back to using WebSQL or localStorage if IndexedDB is not available. 
// So if you can verify that all of your users have devices that support IndexedDB (https://caniuse.com/#search=IndexedDB), then you can safely use 
// `KeyStorage` from v5 as is, if not, you will need to implement a custom adapter for it using localforage to mimic the functionality of v4 sdk

import { EThree } from '@virgilsecurity/e3kit';
import { KeyStorage } from 'virgil-sdk';

(async function () {
    const oldKeyStorage = new KeyStorage({ name: "VirgilSecurityKeys" });
    // function to get Virgil JWT from your backend
    const getToken = () => fetch('/virgil-jwt').then(res => res.json());

    // the useSha256Identifiers is important - the users won't be able to decrypt the previously encrypted data without it
    const e3kit = await EThree.initialize(getToken, { useSha256Identifiers: true });
    
    const privateKeyData = await oldKeyStorage.load('old_user_key');

    // you need to "import" the loaded private key bytes with `e3kit.virgilCrypto.importPrivateKey` to make it usable with e3kit. This will get you back 
    // a PrivateKey object, which you can use to extractPublicKey and save private key to e3kit.keyEntryStorage.

    const privateKey = e3kit.virgilCrypto.importPrivateKey(privateKeyData);
    const publicKey = e3kit.virgilCrypto.extractPublicKey(privateKey);

    await e3kit.keyEntryStorage.save({ name: e3kit.identity, value: privateKey });

    // E3kit publish card under the hood of the register method.
    // Also, e3kit allows only one card per one identity. Thats how we define a user. 
    // There is no restriction from backend side to upload multiple cards for one indentity, but we have client side checks
    // which are not allow to manipulate with identities with multiple cards.
    // So be sure you publish one card for one user, it is imposible to do with documented e3kit methods.
    await e3kit.cardManager.publishCard({
        privateKey, publicKey
    });

    // After card is published and old private key is moved to new storage, you can safely delete private key from old storage
    await oldKeyStorage.remove('old_user_key');
    
    // check if user registered and avalible for search thru e3kit
    const publicKeys = await e3kit.lookupPublicKeys(e3kit.identity);
    console.log(publicKeys)
    
    // old v4 encrypt
    /* const encryptedData = aliceKey
        .signThenEncrypt(message, bobCards) */
    // more documentation https://github.com/VirgilSecurity/virgil-sdk-javascript/tree/v4
    
    // new v5 e3kit encrypt
    // https://developer.virgilsecurity.com/docs/e3kit/end-to-end-encryption/default/
    const encryptedText = await eThree.encrypt('this text will be encrypted', publicKeys);
    
    // You can find more information about e3kit usage here: https://developer.virgilsecurity.com/docs/use-cases/v5/encrypted-communication
})()