exportKeyImages is not working
I am followed the guide [https://github.com/monero-ecosystem/monero-javascript/blob/master/docs/developer_guide/view_only_offline.md](url) for the offline transaction signing. The guide is incorrect because "async" could not be used without await. So i wrote my own code:

```
const monerojs = require("monero-javascript");

if (monerojs.LibraryUtils.WORKER_DIST_PATH.indexOf("C:") == 0 && monerojs.LibraryUtils.WORKER_DIST_PATH.indexOf("file://") == -1)
    monerojs.LibraryUtils.WORKER_DIST_PATH = "file://"+monerojs.LibraryUtils.WORKER_DIST_PATH;

async function test()
{
    const walletNameView = "ViewWallet"
    const walletNameOffline = "OfflineWallet"
    const primaryAddress = "58xgBuuMYGFWnwkBNHZRUn4s613XhQCNx2eMkoqgPJfuZWnXH4HMh9WYQ6KVtLq3TJ4szc1AEZi98H8fLXDekkn7KGgVTMz";

    const privateViewKey = "a15a2245c51fcb50f2bad06a05af68926e4a730efc0cc8b42e9e06a430a84100";
    const privateSpendKey = "e3b0c44298fc1c149afbf4c8996fb92427ae41e4649b934ca495991b7852b800";

    try {
        const RPC = require("./source/private").RPC.txmr || false;
        if (!RPC) throw new Error("RPC not found")
                
        const daemon = await monerojs.connectToDaemonRpc(RPC.host, RPC.user, RPC.password);
        if (!daemon.isConnected) throw new Error("Daemon not connected!");
 
        const height = await daemon.getHeight();   
        
        let viewOnlyWallet = await monerojs.MoneroWalletFull.walletExists(walletNameView) ?
            await monerojs.openWalletFull({
                path: walletNameView,
                networkType: "stagenet",
                password: "supersecretpassword123",
                server: {uri: RPC.host, username: RPC.user, password: RPC.password}
            }) :
            await monerojs.createWalletFull({
                path: walletNameView,
                networkType: "stagenet",
                password: "supersecretpassword123",
                primaryAddress: primaryAddress,
                privateViewKey: privateViewKey,
                restoreHeight: height - 1000,
                server: {uri: RPC.host, username: RPC.user, password: RPC.password}
            });

        if (! await viewOnlyWallet.isConnectedToDaemon()) throw new Error("wallet not connected to daemon")

        if (! await viewOnlyWallet.isSynced())
            await viewOnlyWallet.sync(); 

        // create offline wallet
        let offlineWallet = await monerojs.createWalletFull({
            path: walletNameOffline,
            networkType: "stagenet",
            password: "supersecretpassword123",
            primaryAddress: primaryAddress,
            privateSpendKey: privateSpendKey
        });

        const balance = await viewOnlyWallet.getBalance();
        console.log(balance.toJSValue());

        // export outputs from view-only wallet
        const outputsHex = await viewOnlyWallet.exportOutputs();

        // import outputs to offline wallet
        await offlineWallet.importOutputs(outputsHex);

        // export key images from offline wallet
        let keyImages = await offlineWallet.exportKeyImages();

        await viewOnlyWallet.importKeyImages(keyImages);

        // create unsigned tx using view-only wallet
        ret = await viewOnlyWallet.createTx({
            accountIndex: 0,
            address: primaryAddress,
            amount: "100"
        });

        await viewOnlyWallet.save();
        await viewOnlyWallet.close();
    }
    catch(e) {
        console.log(e);
    }   
}

test();
```

This my code is working well but it seems that the call `await offlineWallet.exportKeyImages();` is returning an incorrect value: Array(0).
Has anyone been able to export key images? Has this feature been tested at all? 
