How does one use getTableItem (TS SDK) against a Table with inner vector data?

[Alexzander-Stone]

Describe your question in detail.

Asked by Kushagra on Discord (#dev-discussions):

Hi, I have a create a table in my move module

struct ReportsObject has key {
       reports: Table<String, vector<Asset>>,
}

I have invoked mu module function and inserted a asset in the table. I have the table handle now.

Now I am trying to fetch table items using

let resources = await aptos.getTableItem({
           handle: <handle>,
           data: {
               key: 'key',
               key_type: 'string',
               value_type: '0x508c3346b5cf6e78a2053da32d2d3529a0758816ba95e97e01b334a1398eff9a::<name>::Asset'
           },
       });

Where they then ask how to supply MoveType's to getTableItem.

What error, if any, are you getting?

I am getting the following error
AptosApiError: Fullnode error: {"message":"'table_item_request' invalid: Unable to parse move type string","error_code":"invalid_input","vm_error_code":null}

What have you tried or looked at? Or how can we reproduce the error?

I have reffered to https://aptos-labs.github.io/ts-sdk-doc/types/Types.MoveType.html
but still unable to find a valid value to pass for key_type

Which operating system are you using?

N/A

Which SDK or tool are you using? (if any)

TypeScript SDK

Describe your environment or tooling in detail

No response

[Alexzander-Stone]

Two Problems Identified

1. key_type

For key_type in getTableItem, you'll need to provide the full struct reference, as defined by MoveType.

A reminder, String is a struct, not a primitive type (e.g. integers and others).

2. value_type

value_type is also misrepresented, since your table contains a vector of Asset, and not just a single Asset.

Solutions

1. key_type

In your example, it would require changes from:

key_type: 'string'

to:

key_type: '0x1::string::String'

I derived this struct reference from the Move reference documentation on Move-stdlib's string.

2. value_type

You'll need to include the vector as part of the string, resulting in changes from:

value_type: '0x508c3346b5cf6e78a2053da32d2d3529a0758816ba95e97e01b334a1398eff9a::<name>::Asset'

to:

value_type: 'vector<0x508c3346b5cf6e78a2053da32d2d3529a0758816ba95e97e01b334a1398eff9a::<name>::Asset>'

---

Useful links

• Aptos-core example of using getTableItem
• Testnet demonstration I deployed
• Helper class used to create the aptos object

Additionally, here's the snippet of Typescript code to retrieve the Table entry from the Testnet demonstration:

let resources = await aptos.getTableItem({
    handle: "0x90b53c1ac994d85235d112f43ff66809af80cf878592a38dacd2442da3b09a77",
    data: {
        key: 'this_is_a_key',
        key_type: '0x1::string::String',
        value_type: 'vector<0x44616c94a2326734bb0d03dd5dc26124f1c041462cc0fccd241b510c414618ca::get_table_item_example::Asset>'
    },
});

which results in:
[ { value: '803' } ]

[Alexzander-Stone]

Hey there, @deepkushagra.

Are you asking how to convert moveString2 into a JS object or the return value of aptos.getTableItem(...)? Or is it something else, entirely?

Also, do you mind sharing a code snippet of the initialization/declaration of the item that you're hoping to convert? It'll help, a ton.

[deepkushagra]

After serialising the string I passed it in for transactions

const moveString2 = new MoveString({name: 'name', add: 'address'});
moveString2.serializeForEntryFunction(new Serializer());
const transaction = await aptos.transaction.build.simple({
            sender: accountAddress,
            data: {
                function: `${accountAddress}::<name>::create_data`,
                functionArguments: [moveString, moveString1, moveString2],
            },
        });
        const committedTransaction = await aptos.signAndSubmitTransaction({
            signer: signerArg,
            transaction,
        });

However, after fetching the the string back from the table.
I have that string which I submitted in the transaction before. I am unable to convert the returned value to a javascript object as before
{name: 'name', add: 'address'}
This was my object initially

[Alexzander-Stone]

So if I'm understanding correctly, @deepkushagra, you're:

1. Creating a MoveString with a JSON object as the content.
2. Serializing the MoveString into bytes to pass into the entry function.
3. Submitting a TX where the previously mentioned MoveString is stored in a Table on-chain.
4. Call aptos.getTableItem(...) against the Table to grab the MoveString that was just stored.
5. Attempt to convert the MoveString back into a JSON object.

But, after step 4, you're not able to convert it back into a JSON object.

If my understanding is complete, can you share a code snippet for steps 4 and 5?

[deepkushagra]

Yes, you understood it right @Alexzander-Stone
My code for step 4-5

let resources4 = await aptos.getTableItem({
            handle: resources2.reports?.handle,
            data: {
                key: 'KEY',
                key_type: '0x1::string::String',
                value_type: 'vector<0x508c3346b5ajd8898a2053da32d2d3529a0758816ba95e97e01b334a1398ensjsa::<name>::Asset>'
            },
        });
        let asset = resources4[0].asset;

asset is printed in console as:- asset: '[object Object]'
I have tried various ways like, parsing it using JSON.parse(). Making a MoveString() from it.
What would be the correct way?

[Alexzander-Stone]

Have you tried using JSON.stringify on the object, before creating a MoveString out of it?

Something like:

const moveString2 = new MoveString(JSON.stringify({name: 'name', add: 'address'}));
...

It appears that MoveString won't automatically stringify the object, resulting in [object Object]. Performing it yourself should fix the problem.