> ## Documentation Index
> Fetch the complete documentation index at: https://mintlify.com/estebanrfp/gdb/llms.txt
> Use this file to discover all available pages before exploring further.

# Method: put(value, id)

> The put method inserts or updates a node in the graph with the specified value and id. If no id is provided, it generates a unique hash based on the value…

### **Method: `put(value, id)`**

#### **Description**

The `put` method inserts or updates a node in the graph with the specified `value` and `id`. If no `id` is provided, it generates a unique hash based on the `value` to serve as the node's identifier. The method ensures that changes are persisted to storage and notifies listeners of the update.

## This method is useful for adding new nodes or updating existing ones in the graph.

#### **Parameters**

1. **`value`** (required):

   * Type: Any serializable data (e.g., object, string, number, etc.)
   * Description: The value to be stored in the node. This represents the data associated with the node.

2. **`id`** (optional):
   * Type: String
   * Description: The unique identifier for the node. If not provided, the method will automatically generate a hash based on the `value`.

***

#### **Returns**

* **`id`**:
  * Type: String
  * Description: The unique identifier (`id`) of the inserted or updated node. If the `id` was not provided, this will be the generated hash.

***

#### **Behavior**

1. **Insertion or Update**:

   * If a node with the given `id` already exists, its `value` is updated.
   * If no node exists with the given `id`, a new node is created.

2. **Automatic ID Generation**:

   * If no `id` is provided, the method generates a unique hash using the `generateHash` function and the serialized `value`.

3. **Persistence**:

   * Changes are saved to persistent storage (e.g., OPFS) using `saveGraphToOPFS`.

4. **Notification**:
   * The method emits an event to notify listeners of the change using `sendData` and `emit`.

***

#### **Examples**

```javascript theme={null}
// (rtc: true) for realtime updates
const db = await gdb("my-db", { rtc: true })
```

##### **Example 1: Inserting a New Node**

```javascript theme={null}
// Add a new node with a specific value
const newNodeId = await db.put({ name: "Alice", age: 25 })

console.log("New Node ID:", newNodeId)
// Output: New Node ID: <generated-hash>
```

In this example:

* A new node is created with the value `{ name: "Alice", age: 25 }`.
* Since no `id` is provided, a unique hash is generated and returned.

***

##### **Example 2: Updating an Existing Node**

```javascript theme={null}
// Add a node with a specific ID
await db.put({ name: "Bob", age: 30 }, "user_123")

// Update the node's value
await db.put({ name: "Bob", age: 31 }, "user_123")

console.log("Updated Node ID:", "user_123")
// Output: Updated Node ID: user_123
```

In this example:

* A node with the ID `"user_123"` is first created.
* Later, the same node is updated with a new value (`age: 31`).

***

##### **Example 3: Automatic ID Generation**

```javascript theme={null}
// Add a node without specifying an ID
const nodeId = await db.put({ product: "Laptop", price: 999 })

console.log("Generated Node ID:", nodeId)
// Output: Generated Node ID: <hash-based-on-value>
```

In this example:

* The method automatically generates a unique hash for the node based on the serialized value `{ product: "Laptop", price: 999 }`.

***

##### **Example 4: Using a Custom ID**

```javascript theme={null}
// Add a node with a custom ID
await db.put({ category: "Electronics" }, "custom_id_456")

console.log("Custom Node ID:", "custom_id_456")
// Output: Custom Node ID: custom_id_456
```

In this example:

* A node is created with a custom ID `"custom_id_456"`.

***

#### **Key Notes**

* **Persistence**: All changes made by `put` are persisted to storage using `saveGraphToOPFS`. This ensures durability of the data.
* **Notifications**: The method emits events to notify listeners of the change. This is useful for real-time updates in applications.
* **Hash Generation**: If no `id` is provided, the method uses `generateHash` to create a unique identifier based on the serialized `value`.

***

#### **Error Handling**

* If the `value` cannot be serialized (e.g., contains circular references), the method may throw an error during hash generation or storage.
* Ensure that the `id` provided (if any) is unique to avoid overwriting existing nodes unintentionally.

***

#### **Use Cases**

1. **Adding New Data**: Use `put` to insert new nodes into the graph when creating records (e.g., users, products).
2. **Updating Existing Data**: Use `put` to modify the value of an existing node by providing its `id`.
3. **Automatic ID Management**: When you don't need to manage IDs manually, rely on the automatic hash generation feature.

***