---
alias: user-guide-automation-task-core-expressionevaluatorgeneric
tags:
- automation tasks
description: "This task evaluates expressions using a math engine, dynamically generating results from input data"
---

# Generic Expression Evaluator

:iot-arithmeticoperation-lg:{style="font-size: 100px"}

The **Generic Expression Evaluator** evaluates mathematical and logical expressions using the mathjs engine. It allows users to perform arithmetic, logical comparisons, and complex mathematical operations on input data, producing computed results dynamically.

![mainImage][mainImage]

!!! note
    This task results from a split of the Expression Evaluator task. It can be used along with [[user-guide-automation-task-core-expressionevaluatorregular]] and [[user-guide-automation-task-core-expressionevaluatorxpath]].

## Workflows

| Data Flow | Control Flow |
| :--------: | :---------: |
| :material-check:{ style="color: #4DB6AC" } | :material-check:{ style="color: #4DB6AC" } |

## Inputs

| Name            | Data Type  | Description |
| --------------- | ---------- | ----------- |
| `<custom list>` | `<custom>` | Defines the input values used in the evaluation |
| Activate        | `any`      | Triggers task execution |

## Outputs

| Name            | Data Type  | Description                                                        |
| --------------- | ---------- | ------------------------------------------------------------------ |
| `<custom list>` | `<custom>` | Defines the output values generated by the evaluation |
|Success | `Boolean` | Returns `true` if the task completes successfully |
| Error | `Error`    | Contains information about any error that occurs |

## Settings

The General tab includes standard task settings and the following parameters:

| Name | Data Type | Values | Default Value | Description |
| ---- | --------- | ------ | ------------- | ----------- |
| Evaluator Behavior | `enum` | `EvaluateAll`<br />`EvaluateUntilTrue` | `EvaluateAll` | Defines whether all expressions are evaluated or evaluation stops after the first true result |
| Clear Inputs | `Boolean` |   | false | When enabled, clears input values after task execution |

![settings][settings]

The Inputs Tab includes the following settings:

| Name | Data Type | Description |
| ---- | --------- | ----------- |
| Name | `String` | Input Name |
| Friendly Name | `String` | The displayed input name |
| Type | `Long`<br />`Decimal`<br />`DateTime`<br />`Boolean`<br />`String`<br />`Integer` | Defines the data type of the input |
| Default Value | `any` | Default value assigned to the input parameter |
| Required | `any` | Indicates if input is required |

![inputs][inputs]

The Outputs Tab includes the following settings:

| Name| Data Type | Description |
| --- | --------- | ----------- |
| Name | `String` | Output Name |
| Friendly Name | `String` | The displayed output name |
| Type | `Long`<br />`Decimal`<br />`DateTime`<br />`Boolean`<br />`String`<br />`Integer` | Defines the data type of the output |
| Expression | `any` | Expression applied to the input data |

![outputs][outputs]

### Evaluator Behavior

The `Generic Expression Evaluator` task uses the mathjs engine, a JavaScript-based library for mathematical and logical computation, as well as some native JavaScript functions.

- `EvaluateUntilTrue`: Stops processing when an expression returns a `true` value and outputs the corresponding result.
- `EvaluateAll`: Evaluates all configured expressions and outputs all results.
- `Clear Inputs`: When enabled, resets the inputs after task execution.

!!! note
    Test `mathjs` expression at <https://jsbin.com/devacu/edit?html,js,output>. Additional documentation is available at <https://mathjs.org/docs/expressions/syntax.html> and <https://mathjs.org/docs/reference/functions.html>.

## Remarks

The **Generic Expression Evaluator** provides flexible operations for transforming input data. While mathjs supports many JavaScript-like functions, it is not a full JavaScript engine; some native JavaScript code may not execute as expected.

[mainImage]: ../images/expression_evaluator_generic.png
[settings]: ../images/expression_evaluator_generic_settings.png
[inputs]: ../images/expression_evaluator_generic_inputs.png
[outputs]: ../images/expression_evaluator_generic_outputs.png