Javascript (vectordb) mergeInsert problem

[tungs2]

Hi everybody,
I have a question regarding mergeInsert using vectordb.

Running this insert

[...]
        // Perform a merge insert operation
        await mergeEmbeddingsToDatabase(embeddingsTable, [
            { hash: 'hash1', vector: [0.15, 0.25], item: "foo updated", usage: 15 },
            { hash: 'hash4', vector: [0.5, 0.5], item: "new item", usage: 30 }
        ]);

[...]

and

async function mergeEmbeddingsToDatabase(table, embeddings) {
    try {
        await table.mergeInsert('hash', embeddings, {
            whenMatchedUpdateAll: true,
            whenNotMatchedInsertAll: true,
            whenNotMatchedBySourceDelete: false
        });
        console.log('Embeddings merged into database successfully.');
[...]

I get this error:
Error during mergeInsert operation: TypeError: failed to downcast any to string

I would be happy about hints what I am doing wrong.

Thank you!

P.s.
Here my complete code:

import lancedb from 'vectordb';

async function runDatabaseOperations() {
    try {
        // Connect to the database
        const db = await lancedb.connect('data/sample-lancedb');

        // Create a table for embeddings
        const embeddingsTable = await db.createTable({
            name: 'embeddings',
            data: [
                { hash: 'hash1', vector: [0.1, 0.2], item: "foo", usage: 10 },
                { hash: 'hash2', vector: [1.1, 1.2], item: "bar", usage: 50 },
            ],
            writeOptions: { writeMode: 'overwrite' }
        });

        // Insert initial data into 'embeddings'
        await embeddingsTable.add([
            { hash: 'hash3', vector: [0.3, 0.4], item: "baz", usage: 20 }
        ]);

        // Perform a merge insert operation
        await mergeEmbeddingsToDatabase(embeddingsTable, [
            { hash: 'hash1', vector: [0.15, 0.25], item: "foo updated", usage: 15 },
            { hash: 'hash4', vector: [0.5, 0.5], item: "new item", usage: 30 }
        ]);

        // Print all entries to verify the merge result
        const allEntries = await embeddingsTable.search(undefined).execute();
        console.log('All database entries: ', allEntries);

    } catch (error) {
        console.error('Error in database operations:', error);
    }
}

async function mergeEmbeddingsToDatabase(table, embeddings) {
    try {
        await table.mergeInsert('hash', embeddings, {
            whenMatchedUpdateAll: true,
            whenNotMatchedInsertAll: true,
            whenNotMatchedBySourceDelete: false
        });
        console.log('Embeddings merged into database successfully.');
    } catch (error) {
        console.error('Error during mergeInsert operation:', error);
        throw error;  // rethrow the error for further handling upstream
    }
}

runDatabaseOperations();