> ## Documentation Index
> Fetch the complete documentation index at: https://docs.keyflow.space/llms.txt
> Use this file to discover all available pages before exploring further.

# Mux

### **Overview:**

The `Mux (Multiplexer)` block is designed to take multiple inputs and output the first non-null value among them. It efficiently manages scenarios involving varied data sources, prioritizing values based on their availability. This block is particularly useful when integrated with a [**Switch Block**](/blocks/flow-control/switch) to enable intelligent decision-making based on specific conditions.

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### Inputs & Outputs

| I/O    | Feature   | Type | Simple Explanation                                                   |
| ------ | --------- | ---- | -------------------------------------------------------------------- |
| input  | `input_1` | any  | The first input value that will be evaluated for non-nullity.        |
| input  | `input_2` | any  | The second input value to be assessed alongside the first one.       |
| output | `output`  | any  | The first non-null value identified among all provided input values. |

<Note>
  To allow accepting more than two inputs, you can click the "+" or "-" icon
  below the input name to add or remove new input handles that you can connect
  other blocks to.
</Note>

***

### Use Cases

Consider how this block enhances efficiency in various situations:

* **Data Prioritization:** When integrating information from sensors in a smart home system, use this block to select the most relevant reading available, ensuring optimal responsiveness.
* **Error Handling:** In scenarios where an application retrieves user profile images from multiple sources (like local storage and cloud), utilize this block to display the first successfully loaded image while bypassing nulls.
* **Config Management:** For dynamically adjusting configurations based on different parameters across environments (development vs production), this tool helps prioritize values effectively without manual oversight.

In summary, whenever your workflow involves needing a reliable single datum out of several alternatives, the `Mux (Multiplexer)` block proves invaluable!