Begin by setting up your development environment. Ensure that you have Node.js installed on your machine. Next, install the MongoDB Node.js driver and the Convex SDK by running `npm install mongodb @convex-dev/convex`. This will allow you to interact with both your MongoDB database and Convex directly through JavaScript.

Create a Node.js script to connect to your MongoDB instance. Use the MongoDB Node.js driver to establish a connection. Here's a snippet to get you started:
```javascript
const { MongoClient } = require('mongodb');
const uri = "your_mongodb_uri";
const client = new MongoClient(uri, { useNewUrlParser: true, useUnifiedTopology: true });

async function connectToMongoDB() {
try {
await client.connect();
console.log("Connected to MongoDB");
} catch (error) {
console.error("Error connecting to MongoDB:", error);
}
}
connectToMongoDB();
```

Once connected, query the MongoDB collection to retrieve the data you want to transfer. Use MongoDB's `find` method to fetch the documents:
```javascript
async function fetchMongoData() {
try {
const database = client.db('your_database_name');
const collection = database.collection('your_collection_name');
const data = await collection.find({}).toArray();
console.log("Data retrieved from MongoDB:", data);
return data;
} catch (error) {
console.error("Error fetching data from MongoDB:", error);
return [];
}
}
```

Initialize the Convex client in your script. Ensure that your Convex project is set up and you have access credentials. Use the Convex SDK to authenticate and prepare to send data:
```javascript
const { ConvexHttpClient } = require('@convex-dev/convex');

const convexClient = new ConvexHttpClient({
project: 'your_convex_project_id',
accessKey: 'your_convex_access_key'
});
```

Depending on your data structure, you might need to transform the data retrieved from MongoDB to fit into Convex. This could involve renaming fields, changing data types, or other modifications to ensure compatibility:
```javascript
function transformData(data) {
return data.map(doc => ({
// Transform the document as needed
id: doc._id.toString(), // Example transformation
...doc // Include other fields
}));
}
```

With the Convex client set up and your data transformed, insert the data into Convex. Use the Convex client to create new documents:
```javascript
async function insertDataIntoConvex(data) {
try {
for (const doc of data) {
await convexClient.insert('your_convex_table_name', doc);
}
console.log("Data inserted into Convex successfully");
} catch (error) {
console.error("Error inserting data into Convex:", error);
}
}
```

Execute your script by running `node your_script_name.js`. Monitor the console output to verify that connections are successful and data is being transferred. Finally, log into your Convex dashboard to ensure that the data has been accurately moved and is available in your specified table.

By following these steps, you can manually transfer data from MongoDB to Convex without using third-party connectors or integrations.